title: iOS app freezes when tapping on notification action
body: <pre><code> -(void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)())completionHandler{
  
   dispatch_async(dispatch_get_main_queue(), ^{
   LSAddActivityViewController *addVC = [[LSAddActivityViewController alloc]init];
             addVC.leadID = LeadID;
             addVC.activityType = @"Notable Activity";
             [((UINavigationController *)self.window.rootViewController) 
             pushViewController:addVC animated:YES];
  
  });
  completionHandler();
  }
  </code></pre>
  
  <p>Above code executes when an Action is tapped on <code>UNUserNotificationCenter</code> local notification. <code>LSAddActivityViewController</code> is being launched with proper UI but app freezes, no touch is working anywhere on the app. </p>
  
  <p><strong>NOTE -</strong>  On orientation change UI is being re-drawn perfectly. <code>self.view.userInterationEnabled</code> is true always.</p>