message: fix: Unhandled exception Str Column Type
diff: @@ -312,9 +312,9 @@ class BaseDatasource(
  for metric in utils.get_iterable(form_data.get(metric_param) or []):
  metric_names.add(utils.get_metric_name(metric))
  if utils.is_adhoc_metric(metric):
  - column_names.add(
  - (metric.get("column") or {}).get("column_name")
  - )
  + column = metric.get("column") or {}
  + if column_name := column.get("column_name"):
  + column_names.add(column_name)
  # Columns used in query filters
  column_names.update(
  