fix: changing ball spawning point to avoid context errors

lib/game/pinball_game.dart

@@ -142,4 +142,10 @@ class PinballGame extends Forge2DGame with FlameBloc, KeyboardEvents {
     super.onAttach();
     spawnBall();
   }
+
+  @override
+  void onAttach() {
+    super.onAttach();
+    spawnBall();
+  }
 }