fix(android): Add AGP 8 support with namespace property

[Gustl22]

Description

Cherry-pick of #1503

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs:, chore: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation and added dartdoc comments with ///, where necessary.
• I have updated/added relevant examples in example.

Breaking Change

• Yes, this is a breaking change.
• No, this is not a breaking change.

Optional Migration instructions

You can upgrade your Android project to use AGP 8. In your android/build.gradle :

buildscript {
  // ...
  dependencies {
    classpath 'com.android.tools.build:gradle:8.0.1'
    // ...
  }
}

If doing so, also don't forget to add a namespace in the android section of android/app/build.gradle :

android {
  // ...
  namespace 'your.namespace'
}

Then can also remove the package property in your android/app/src/main/AndroidManifest.xml

Related Issues

#1503