message: Capture error when celery back-end does not support forgetting tasks
diff: @@ -2240,7 +2240,13 @@ class Superset(BaseSupersetView): # pylint: disable=too-many-public-methods
  # Explicitly forget the task to ensure the task metadata is removed from the
  # Celery results backend in a timely manner.
  + try:
  task.forget()
  + except NotImplementedError:
  + logger.warning(
  + "Unable to forget Celery task as backend"
  + "does not support this operation"
  + )
  except Exception as ex: # pylint: disable=broad-except
  logger.exception("Query %i: %s", query.id, str(ex))
  msg = _(
  