[flutter_local_notifications] Update gradle versions and declarations for example app

[martin-bertele]

Followed https://docs.flutter.dev/release/breaking-changes/flutter-gradle-plugin-apply

and updated AGP and kotlin versions.

[Levi-Lesches]

Hey @martin-bertele, Maiku ran the CI just now, seems you're getting Java mismatches:

ERROR: ERROR: FAILURE: Build failed with an exception.

* Where:
Build file '/home/runner/work/flutter_local_notifications/flutter_local_notifications/flutter_local_notifications/example/android/app/build.gradle' line: 2

* What went wrong:
An exception occurred applying plugin request [id: 'com.android.application']
> Failed to apply plugin 'com.android.internal.application'.
   > Android Gradle plugin requires Java 17 to run. You are currently using Java 11.
      Your current JDK is located in /usr/lib/jvm/temurin-11-jdk-amd[64](https://github.com/MaikuB/flutter_local_notifications/actions/runs/12137271322/job/34172105150?pr=2482#step:5:65)
      You can try some of the following options:
       - changing the IDE settings.
       - changing the JAVA_HOME environment variable.
       - changing `org.gradle.java.home` in `gradle.properties`.

Notice how the Integrations tests are the only ones that passed on Android -- that's because they properly set up Java:

      - uses: actions/setup-java@v3
        with:
          distribution: 'zulu'
          java-version: '17'

Can you copy and paste that into the other failing tests as well?

[MaikuB]

@martin-bertele I believe the build is failing as it needs changes that I tried to do in #2488 but looks like that would also need the changes done in this PR. Are you able to incorporate the changes I tried to do in this PR? Would help to ensure everything is green

Edit: missed that @Levi-Lesches made similar comments

[Levi-Lesches]

@MaikuB If you can change your #2488 to be based on Martin's branch, that should allow you to test both changes at once.

Also, I wanted to point out that this PR upgrades the Android Gradle Plugin to 8.4, coming from 7.3.1. That shouldn't be an issue though. This comment points out that it would break users of AGP 4.1, but... we've been mandating AGP >= 7.3.1 for a while now, and #1970, which is the real backwards-incompatible change, was merged in April 2023 with no major complaints.

[MaikuB]

@Levi-Lesches yep I know. Provided the PR has permissions for it, I could've even pushed changes directly to @martin-bertele's but avoided doing so in case @martin-bertele was going to make changes since you mentioned what can be done already and could I end up wasting @martin-bertele's time. Since we've not heard back though I'll look to do so later if @martin-bertele hasn't gotten to do by the time I can to it

[martin-bertele]

Unfortunately I got sick, if I need to change any permissions let me know this I can still do, otherwise I m available next week. Thank you

[MaikuB]

It's quite possible you ticked it as I believe it's ticked by default but it's to do with this one https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork

[martin-bertele]

@Levi-Lesches @MaikuB you can go ahead and copy over any lines from this pr to the work you have, really use the way that works with minimum effort for you. It's been a coincidence that you were to upgrade the sample too.
I got it to run and thought then I ll contribute. :)

AGP and kotlin I was forced to upgrade since there was some compatibility complains.
After that, it built successfully.

Permissions on PR I am not sure how to set, let me know what you need there. Thanks for your great package!

[MaikuB]

@martin-bertele all good as the permissions are fine as I've been able to push changes directly. Once it's all green and I've done some more testing/reviewing then will merge it in

[Levi-Lesches]

Compiles on Flutter 3.27.0 with no issues or warnings!