Migrate share_handler_android to Flutter built-in Kotlin support

[aiviapp]

Flutter 3.44.4 reports that share_handler_android 0.0.11 still applies the legacy Kotlin Gradle Plugin (KGP), which future Flutter versions will no longer support.

The current android/build.gradle unconditionally applies kotlin-android and configures kotlinOptions. Please migrate the plugin to AGP 9 built-in Kotlin support following Flutter's plugin-author guide:

https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors

Observed warning:

Your app uses the following plugins that apply Kotlin Gradle Plugin (KGP): share_handler_android