Reverts flutter/flutter#140115

Initiated by: bartekpacia

Reason for reverting: broke the tree

- [`Linux firebase_abstract_method_smoke_test`](https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20firebase_abstract_method_smoke_test/15844/overview)
- [`Linux_android android_view_scroll_perf__timeline_summary`](https://ci.chromium.org/ui/p/flutter/builders/prod/Linux_android%20android_view_scroll_perf__timeline_summary/13453/overview)
- [`Linux_android platform_views

Original PR Author: bartekpacia

Reviewed By: {gmackall}

This change reverts the following previous change:
Original Description:
This PR updates almost* all Gradle buildscripts in the Flutter repo the `example` and `dev` (in particular, in `dev/integration_tests` and in `dev/benchmarks`) directories to apply Flutter's Gradle plugins using the declarative `plugins {}` block.

*almost, because:
- add-to-app (aka hybrid) apps are not migrated (related https://github.com/flutter/flutter/issues/138756)
- apps that purposefully use build files to ensure backward compatibility (e.g. [`gradle_deprecated_settings`](https://github.com/flutter/flutter/tree/3.16.0/dev/integration_tests/gradle_deprecated_settings))