check that the change collection has changes instead of checking that…

… it exists

dbt/adapters/bigquery/relation.py

@@ -95,7 +95,7 @@ def materialized_view_config_changeset(
                 context=new_materialized_view.cluster,
             )
 
-        if config_change_collection:
+        if config_change_collection.has_changes:
             return config_change_collection
         return None