Restoring support for swipe right gesture to play previous track in Music app

Author: Joel Hill

src/displayapp/screens/Music.cpp

@@ -275,6 +275,10 @@ bool Music::OnTouchEvent(Pinetime::Applications::TouchEvents event) {
       musicService.event(Controllers::MusicService::EVENT_MUSIC_NEXT);
       return true;
     }
+    case TouchEvents::SwipeRight: {
+      musicService.event(Controllers::MusicService::EVENT_MUSIC_PREV);
+      return true;
+    }
     default: {
       return false;
     }