fix: dict bug on QueryContextFactory (#23093)

Co-authored-by: ok9897 <ok9897@krafton.com>

superset/common/query_context_factory.py

@@ -121,7 +121,7 @@ def _apply_granularity(
         datasource: BaseDatasource,
     ) -> None:
         temporal_columns = {
-            column.column_name
+            column["column_name"] if isinstance(column, dict) else column.column_name
             for column in datasource.columns
             if (column["is_dttm"] if isinstance(column, dict) else column.is_dttm)
         }