Fix preference name

aleksis/apps/untis/util/mysql/util.py

@@ -168,5 +168,5 @@ def move_weekday_to_range(time_periods_ref: dict, weekday: int) -> int:
 
 def is_untis_primary_source(model: Type[Model]) -> bool:
     """Check if Untis is primary source for the model."""
-    allowed_content_types = get_site_preferences()["untis_primary_sources"]
+    allowed_content_types = get_site_preferences()["untis_mysql__data_types_primary_source"]
     return ContentType.objects.get_for_model(model) in allowed_content_types