[gen-l10n] Invalid dart file is generated by gen-l10n when (there are no "regular" characters in front of a dollar sign) and (there is a select clause in a message)

### Is there an existing issue for this?

- [X] I have searched the [existing issues](https://github.com/flutter/flutter/issues)
- [X] I have read the [guide to filing a bug](https://flutter.dev/docs/resources/bug-reports)

### Steps to reproduce

 1. Clone repository https://github.com/mshurkaeu-public/flutter-bugs-I-found-or-reported.git
 2. Switch into branch main.
 3. Navigate to folder 03-gen-l10n-dollar-sign+select-clause.
 4. Run command
 ```bash
 flutter gen-l10n
```
5. Check resulting file .dart_tool/flutter_gen/gen_l10n/app_localizations_en.dart. Methods helloBugManifistation1 and helloBugManifistation2 are generated incorrectly. And thus the whole generated file is invalid.

### Expected results

The generated app_localizations_en.dart file contains correctly escaped dollar sign:

```dart
  @override
  String helloBugManifistation1(String selectPlaceholder) {
    String _temp0 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': 'message',
        'other': 'messageOther',
      },
    );
    return '\$nice_bug\nHello Bug! Manifistation #1 $_temp0';
  }

  @override
  String helloBugManifistation2(String selectPlaceholder) {
    String _temp0 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': '',
        'other': '',
      },
    );
    String _temp1 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': 'message',
        'other': 'messageOther',
      },
    );
    return '${_temp0}\$nice_bug\nHello Bug! Manifistation #2 $_temp1';
  }
```

### Actual results

The generated app_localizations_en.dart file is invalid:

```dart
  @override
  String helloBugManifistation1(String selectPlaceholder) {
    String _temp0 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': 'message',
        'other': 'messageOther',
      },
    );
    return '${nice_bug
Hello Bug! Manifistation #1 }$_temp0';
  }

  @override
  String helloBugManifistation2(String selectPlaceholder) {
    String _temp0 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': '',
        'other': '',
      },
    );
    String _temp1 = intl.Intl.selectLogic(
      selectPlaceholder,
      {
        'case': 'message',
        'other': 'messageOther',
      },
    );
    return '$_temp0${nice_bug
Hello Bug! Manifistation #2 }$_temp1';
  }
```

### Code sample

<details><summary>Full code of the example is available in repository https://github.com/mshurkaeu-public/flutter-bugs-I-found-or-reported.git. Branch main. Folder 03-gen-l10n-dollar-sign+select-clause.</summary>

```json
{
  "helloBugManifistation1": "$nice_bug\nHello Bug! Manifistation #1 {selectPlaceholder, select, case{message} other{messageOther}}",
  "@helloBugManifistation1": {
    "description": "This is a demo #1 of the bug",
    "placeholders": {
      "selectPlaceholder": {
        "type": "String"
      }
    }
  },
  "helloBugManifistation2": "{selectPlaceholder, select, case{} other{}}$nice_bug\nHello Bug! Manifistation #2 {selectPlaceholder, select, case{message} other{messageOther}}",
  "@helloBugManifistation2": {
    "description": "This is a demo #2 of the bug",
    "placeholders": {
      "selectPlaceholder": {
        "type": "String"
      }
    }
  },
  "workaroundTheBug": "\u200B$nice_bug\nHello Bug! A workaround... {selectPlaceholder, select, case{message} other{messageOther}}",
  "@helloBug1": {
    "description": "This is a demo of a workaround for the bug",
    "placeholders": {
      "selectPlaceholder": {
        "type": "String"
      }
    }
  }
}
```

</details>


### Screenshots or Video

_No response_

### Logs

<details><summary>Logs</summary>

```console
flutter --verbose gen-l10n
[  +13 ms] executing: uname -m
[   +8 ms] Exit code 0 from: uname -m
[        ] x86_64
[        ] executing: [/home/vboxuser/snap/flutter/common/flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[   +7 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[   +1 ms] 4d9e56e694b656610ab87fcf2efbcd226e0ed8cf
[        ] executing: [/home/vboxuser/snap/flutter/common/flutter/] git tag --points-at 4d9e56e694b656610ab87fcf2efbcd226e0ed8cf
[  +15 ms] Exit code 0 from: git tag --points-at 4d9e56e694b656610ab87fcf2efbcd226e0ed8cf
[        ] 3.7.12
[   +9 ms] executing: [/home/vboxuser/snap/flutter/common/flutter/] git rev-parse --abbrev-ref --symbolic @{upstream}
[   +3 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{upstream}
[        ] origin/stable
[        ] executing: [/home/vboxuser/snap/flutter/common/flutter/] git ls-remote --get-url origin
[   +1 ms] Exit code 0 from: git ls-remote --get-url origin
[        ] https://github.com/flutter/flutter.git
[  +21 ms] executing: [/home/vboxuser/snap/flutter/common/flutter/] git rev-parse --abbrev-ref HEAD
[   +2 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[        ] stable
[  +14 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[   +2 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[  +24 ms] Artifact Instance of 'MaterialFonts' is not required, skipping update.
[  +14 ms] Artifact Instance of 'GradleWrapper' is not required, skipping update.
[   +8 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[        ] Artifact Instance of 'FlutterSdk' is not required, skipping update.
[        ] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FontSubsetArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'PubDependencies' is not required, skipping update.
[  +53 ms] Because l10n.yaml exists, the options defined there will be used instead.
           To use the command line arguments, delete the l10n.yaml file in the Flutter project.
           
           
[ +145 ms] "flutter gen-l10n" took 264ms.
[   +1 ms] Running 0 shutdown hooks
[   +1 ms] Shutdown hooks complete
[        ] exiting with code 0
```

</details>


### Flutter Doctor output

<details><summary>Doctor output</summary>

```console
flutter doctor -v
[✓] Flutter (Channel stable, 3.7.12, on Ubuntu 22.10 5.19.0-40-generic, locale en_US.UTF-8)
    • Flutter version 3.7.12 on channel stable at /home/vboxuser/snap/flutter/common/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 4d9e56e694 (7 days ago), 2023-04-17 21:47:46 -0400
    • Engine revision 1a65d409c7
    • Dart version 2.19.6
    • DevTools version 2.20.1

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.2)
    • Android SDK at /home/vboxuser/Android/Sdk
    • Platform android-33-ext4, build-tools 33.0.2
    • Java binary at: /snap/android-studio/125/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • Chrome at google-chrome

[✓] Linux toolchain - develop for Linux desktop
    • clang version 10.0.0-4ubuntu1
    • cmake version 3.16.3
    • ninja version 1.10.0
    • pkg-config version 0.29.1

[✓] Android Studio (version 2021.3)
    • Android Studio at /snap/android-studio/125/android-studio
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)

[✓] VS Code (version 1.77.3)
    • VS Code at /usr/share/code
    • Flutter extension version 3.62.0

[✓] Connected device (2 available)
    • Linux (desktop) • linux  • linux-x64      • Ubuntu 22.10 5.19.0-40-generic
    • Chrome (web)    • chrome • web-javascript • Google Chrome 112.0.5615.121

[✓] HTTP Host Availability
    • All required HTTP hosts are available

• No issues found!
```

</details>


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[gen-l10n] Invalid dart file is generated by gen-l10n when (there are no "regular" characters in front of a dollar sign) and (there is a select clause in a message) #125461

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[gen-l10n] Invalid dart file is generated by gen-l10n when (there are no "regular" characters in front of a dollar sign) and (there is a select clause in a message) #125461

Description

Is there an existing issue for this?

Steps to reproduce

Expected results

Actual results

Code sample

Screenshots or Video

Logs

Flutter Doctor output

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

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Development

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