Fix AccessibilityFeatures.disableAnimations flag on Android 12+ - #53428

Thanks for reviewing @jonahwilliams and @reidbaker. I actually discovered there's a second bug in AccessibilityBridge.java, which prevents animations from being disabled when the app is launched. setBoldTextFlag() contains a bit twiddling bug which causes all the other flags to be cleared. On app launch the following happens, provided the user has set the following accessibility settings: "Remove animations" on, "Bold text" off.

1. animationScaleObserver.onChange() sets the DISABLE_ANIMATION flag.
2. Immediately after, setBoldTextFlag() clears all flags due to the bit twiddling bug (it was obviously meant to only clear the BOLD_TEXT flag).

I've pushed a second commit that fixes this as well, and I now believe flutter/flutter#130976 is fully resolved. To verify, I have created a simple Flutter app that displays the value of MediaQuery.disableAnimationsOf(context), and I have checked that it is correct both on launch, and when changing the accessibility setting while the app is running. I've attached screen recordings from a Pixel 4 API 29 (Android 10), a Pixel 6 API 33 (Android 13) and a Samsung Galaxy S20 API 33 (Android 13). Note that when changing the "Remove animations" setting, it takes a few seconds before the flag updates after switching back to the app. This happens in native apps as well, so I believe it's just Android being Android, and not a problem with the Flutter engine.

Test app:

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: Scaffold(
        body: Center(
          child:
              Text('MediaQueryData.disableAnimations=${MediaQuery.disableAnimationsOf(context)}'),
        ),
      ),
    );
  }
}

@reidbaker, I’ve expanded the itSetsBoldTextFlagCorrectly test to verify that clearing the bold text flag doesn’t affect other flags. This change was a bit involved because AccessibilityBridge only manipulates the bold text flag in its constructor, so I had to recreate the instance using setUpBridge.