Support flutter build x for Mac Designed for iPad apps on arm64 Macs #141332
Description
Implement flutter build for Mac Designed for iPad that builds an iPad application package that can be run on arm64 Macs.
From Xcode it's building the into path/to/deriveddata/Build/Products/Debug-iphoneos/.XCInstall/Test Create.app
$ ll -R /Users/m/Library/Developer/Xcode/DerivedData/Runner-gnengnkipgqsumexkvwkdczgvrst/Build/Products/Debug-iphoneos/.XCInstall/Test\ Create.app
total 0
drwxr-xr-x@ 4 m primarygroup 128 Jan 9 15:57 .
drwxr-xr-x 9 m primarygroup 288 Jan 10 09:49 ..
lrw-r--r-- 1 m primarygroup 18 Jan 9 15:57 WrappedBundle -> Wrapper/Runner.app
drwxr-xr-x 4 m primarygroup 128 Jan 9 15:57 Wrapper
/Users/m/Library/Developer/Xcode/DerivedData/Runner-gnengnkipgqsumexkvwkdczgvrst/Build/Products/Debug-iphoneos/.XCInstall/Test Create.app/Wrapper:
total 8
drwxr-xr-x 4 m primarygroup 128 Jan 9 15:57 .
drwxr-xr-x@ 4 m primarygroup 128 Jan 9 15:57 ..
-rw-r--r-- 1 m primarygroup 618 Jan 9 15:57 BundleMetadata.plist
drwxr-xr-x 13 m primarygroup 416 Jan 9 15:57 Runner.app
What this looks like will depend on how we create this bundle as part of flutter run and drive #141328
flutter build ios -d designed-for-ipad that checks for this well-known identifier and does the special wrapper flow?
An entirely new BuildSubCommand flutter build designed-for-ipad?
Whatever choice is made, validate --config-only works (sets up the Xcode project for iOS but don't actually build the app).
Part of #125741