message: [druid] fix FilterBox viz gets timestamps as values if granularity <> all
diff: @@ -931,7 +931,6 @@ class DruidDatasource(Model, BaseDatasource):
  if 'is_timeseries' in query_obj else True
  if (
  not is_timeseries and
  - query_obj['granularity'] == "all" and
  DTTM_ALIAS in df.columns):
  del df[DTTM_ALIAS]
  