Remove unused imports from AndroidPlugin.java

Deleted unused imports for Handler, Looper, and Process to clean up the code and improve maintainability.

Author: FeodorFitsner

src/serious_python_android/android/src/main/java/com/flet/serious_python_android/AndroidPlugin.java

@@ -5,9 +5,6 @@
 import androidx.annotation.NonNull;
 import android.system.Os;
 import android.content.Intent;
-import android.os.Handler;
-import android.os.Looper;
-import android.os.Process;
 
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
 import io.flutter.embedding.engine.plugins.activity.ActivityAware;