fix: Apply normalization to all dttm columns (#25147)

(cherry picked from commit 58fcd292a9)

superset/common/query_context_processor.py

@@ -285,10 +285,11 @@ class QueryContextProcessor:
         datasource = self._qc_datasource
         labels = tuple(
             label
-            for label in [
+            for label in {
                 *get_base_axis_labels(query_object.columns),
+                *[col for col in query_object.columns or [] if isinstance(col, str)],
                 query_object.granularity,
-            ]
+            }
             if datasource
             # Query datasource didn't support `get_column`
             and hasattr(datasource, "get_column")