Fix Flutter deprectation warnings for Android

[MathJud]

The following deprecation warnings appear when running flutter build for Android

You are applying Flutter's app_plugin_loader Gradle plugin imperatively using the apply script method, which is deprecated and will be removed in a future release. Migrate to applying Gradle plugins with the declarative plugins block: https://flutter.dev/go/flutter-gradle-plugin-apply

You are applying Flutter's main Gradle plugin imperatively using the apply script method, which is deprecated and will be removed in a future release. Migrate to applying Gradle plugins with the declarative plugins block: https://flutter.dev/go/flutter-gradle-plugin-apply

Note: /home/sojus/src/qaul/qaul-libp2p_store/qaul_ui/build/blemodule/generated/source/proto/debug/javalite/qaul/sys/ble/BleOuterClass.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: /home/sojus/.pub-cache/hosted/pub.dev/uni_links-0.5.1/android/src/main/java/name/avioli/unilinks/UniLinksPlugin.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.