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))
* Revert "Mark last failing test after gradle update as flaky. (#91423)"
This reverts commit 46a52d03bd.
* Revert "fix android template for Gradle 7 (#91411)"
This reverts commit 51d06d537f.
* Revert "Add explicit version for mac and windows openjdk. (#91408)"
This reverts commit bf429f2771.
* Revert "Update the openjdk version used by linux android tests. (#91405)"
This reverts commit 2144ab8b45.
* Revert "Migrate to Gradle 7.0.2 / AGP 7.0.1 (#90642)"
This reverts commit b6459f9b63.
