message: [druid] Fix datasource column enumeration
diff: @@ -166,6 +166,7 @@ class DruidCluster(Model, AuditMixinNullable):
  for i in range(0, len(ds_refresh)):
  datasource = ds_refresh[i]
  cols = metadata[i]
  + if cols:
  col_objs_list = (
  session.query(DruidColumn)
  .filter(DruidColumn.datasource_name == datasource.datasource_name)
  