Bump almost all tests to AGP 8.1 and Gradle 8.3
Flutter gallery is excluded, because it uses discontinued plugins that in turn use old Gradle versions, and that prevents upgrading. Will take some extra work to figure out what to do there.
Should bump templates next
Entire PR generated with the lockfile generation script, except for:
1. changes within `dev/integration_tests/gradle_deprecated_settings/android/`, which must be done manually (and exclusion of the gallery for reason mentioned above).
2. Changes to many `AndroidManifest.xml` files to remove the `package` attribute and instead set that same value in the `build.gradle`, in the `namespace` attribute of the `android` closure (corresponds to an AGP behavior change, see https://d.android.com/r/tools/upgrade-assistant/set-namespace).
3. Removes the use of the `battery` plugin in `android_embedding_v2_smoke_test` because the plugin is discontinued, unused, and blocks upgrading the AGP version for that app because the discontinued plugin itself uses a very old AGP version.
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.
