In #122336 we migrated the principal class from NSApplication to
FlutterApplication in the app Info.plist. We removed the need for
FlutterApplication in https://github.com/flutter/engine/pull/40929. This
reverses the migration for anyone who previously upgraded on the Flutter
master branch.

Issue: https://github.com/flutter/flutter/issues/30735

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- [X] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [X] I signed the [CLA].
- [X] I listed at least one issue that this PR fixes in the description
above.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I added new tests to check the change I am making, or this PR is
[test-exempt].
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If you need help, consider asking for advice on the #hackers-new channel
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[macOS] Eliminate explicit main window init()

Revert unintentional changes to Info.plist files

Add support for application exit requests

Add macos project auto migration code for FlutterApplication

* Add gems as a dep - fails without

* Add missing entitlements to run app on macos
Co-authored-by: a-wallen <stephenwallen@google.com>

Increases the minimum macOS deployment target from macOS 10.13 (High Sierra) to 10.14 (Mojave) in the macOS app templates.

Includes:
* Update migration for macOS 10.11 apps to upgrade to 10.14
* Adds migration for macOS 10.13 apps to upgrade to 10.14
* Apply migration to all examples, and integration tests

This does not increase version in the plugin templates since those will need to wait until the 10.14 framework rolls to stable channel, so new plugins can build with apps created with `flutter create` on stable channel.

Issue: https://github.com/flutter/flutter/issues/114445
See RFC: http://flutter.dev/go/flutter-drop-macOS-10.13-2022-q4
See previous patch: https://github.com/flutter/flutter/pull/107689

This reverts commit 0b6b3eec.

This reverts commit 70f8fdee.

This reverts commit e4fbb1ab.