title: Notification not displayed with action buttons when app is killed ios
body: <p>I've done following code to display action buttons while notification comes using one signal. But when app is killed notification is not coming. It's working properly in background/foreground mode. But when app is not in tray even notification stop coming. Without action buttons it's working perfectly.</p>
  
  <pre><code>UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
  center.delegate = self;
  [center requestAuthorizationWithOptions:(UNAuthorizationOptionSound | UNAuthorizationOptionAlert | UNAuthorizationOptionBadge) completionHandler:^(BOOL granted, NSError * _Nullable error)
   {
       if( !error ) {
           [[UIApplication sharedApplication] registerForRemoteNotifications];
  
           NSLog( @"Push registration success." );
  
       } else {
           NSLog( @"Push registration FAILED" );
  
  }];
  
  UNNotificationCategory *modifyCategory = [UNNotificationCategory categoryWithIdentifier:CYLInviteCategoryIdentifier actions:@[] intentIdentifiers:@[] options:UNNotificationCategoryOptionNone];
  
  UNNotificationAction* snoozeAction = [UNNotificationAction
                                            actionWithIdentifier:@"ACCEPT_ACTION"
                                            title:@"Accept"
                                            options:UNNotificationActionOptionForeground];
  
  UNNotificationAction* stopAction = [UNNotificationAction
                                          actionWithIdentifier:@"DECLINE_ACTION"
                                          title:@"Decline"
                                          options:UNNotificationActionOptionDestructive];
  
  UNNotificationCategory* actionCategory = [UNNotificationCategory
                                                 categoryWithIdentifier:@"INCOMING_CALL"
                                                 actions:@[snoozeAction, stopAction]
                                                 intentIdentifiers:@[]
                                                 options:UNNotificationCategoryOptionNone];
  
  [center setNotificationCategories:[NSSet setWithObjects: modifyCategory, actionCategory,
                                         nil]];
  </code></pre>