onGroupMemberUnbanned method
      
  
void
onGroupMemberUnbanned()
       
    
    
override
    Implementation
@override
void onGroupMemberUnbanned(cc.Action action, User unbannedUser,
    User unbannedBy, Group unbannedFrom) {
  if (_messageCategoryTypeCheck(action)) {
    if (group?.guid == unbannedFrom.guid) {
      _onMessageReceived(action);
    }
  }
}