Merge pull request #2079 from nextcloud/backport/2078/stable21

[stable21] fix: add nil check to prevent crash when adding room.token to dictionary

Author: SystemKeeper

NextcloudTalk/RoomsTableViewController.m

@@ -1307,7 +1307,7 @@ - (void)createRoomForSelectedUser:(NCUser *)user
      ofType:kNCRoomTypeOneToOne
      andName:nil
      completionBlock:^(NCRoom *room, NSError *error) {
-        if (!error) {
+        if (!error && room.token != nil) {
             [self.navigationController dismissViewControllerAnimated:YES completion:^{
                 [[NSNotificationCenter defaultCenter] postNotificationName:NCSelectedUserForChatNotification
                                                                     object:self