message: add sounds to ios when on vibrate mode
diff: #import <React/RCTBundleURLProvider.h>
  #import <React/RCTRootView.h>
  +#import <AVFoundation/AVFoundation.h>
  +
  @import Firebase;
  @implementation AppDelegate
  rootViewController.view = rootView;
  self.window.rootViewController = rootViewController;
  [self.window makeKeyAndVisible];
  +
  + // for audio on vibrate mode with YouTubeStandaloneIOS
  + [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error: nil];
  +
  return YES;
  }
  