Apply suggestions from code review

Co-authored-by: Allison Ryan <77211884+allisonryan0002@users.noreply.github.com>

packages/pinball_audio/lib/src/pinball_audio.dart

@@ -150,7 +150,7 @@ class _SingleLoopAudio extends _LoopAudio {
   }
 }
 
-class _SingleAudioPoll extends _Audio {
+class _SingleAudioPool extends _Audio {
   _SingleAudioPoll({
     required this.path,
     required this.createAudioPool,

packages/pinball_components/test/src/components/flipper/behaviors/flipper_moving_behavior_test.dart

@@ -111,7 +111,7 @@ void main() {
     );
 
     flameTester.test(
-      'play the flipper sound when moving up',
+      'plays the flipper sound when moving up',
       (game) async {
         final audioPlayer = _MockPinballAudioPlayer();
         final bloc = _MockFlipperCubit();