Updates Gradle version for Flutter project templates and integration tests to at least 7.6.3 (changed all of those with versions below it) to fix security vulnerability.
Part of fix for https://github.com/flutter/flutter/issues/138336.
Upgrades agp versions and lockfiles for `dev/`. Also changes the lockfile generation script to represent the newer form of the `settings.gradle` template, and therefore also propagates these changes.
~~Potentially related to https://github.com/flutter/flutter/issues/134419~~, but worth doing anyways. (not actually related)
Reverts flutter/flutter#137191
Initiated by: camsim99
This change reverts the following previous change:
Original Description:
Adds support for Android 34 in the following ways:
- Bumps integration tests compile SDK versions 33 --> 34
- Bumps template compile SDK version 33 --> 34
- Also changes deprecated `compileSdkVersion` to `compileSdk`
Part of https://github.com/flutter/flutter/issues/134220
Adds support for Android 34 in the following ways:
- Bumps integration tests compile SDK versions 33 --> 34
- Bumps template compile SDK version 33 --> 34
- Also changes deprecated `compileSdkVersion` to `compileSdk`
Part of https://github.com/flutter/flutter/issues/134220
