message: Moving homogenize_types to after no data exception
diff: @@ -1331,10 +1331,10 @@ class DruidDatasource(Model, BaseDatasource):
  client=client, query_obj=query_obj, phase=2)
  df = client.export_pandas()
  - df = self.homogenize_types(df, query_obj.get('groupby', []))
  -
  if df is None or df.size == 0:
  raise Exception(_('No data was returned.'))
  +
  + df = self.homogenize_types(df, query_obj.get('groupby', []))
  df.columns = [
  DTTM_ALIAS if c in ('timestamp', '__time') else c
  for c in df.columns
  