Fix unique_user_filter_index schema update

synapse/storage/schema/delta/56/unique_user_filter_index.py

@@ -24,8 +24,8 @@ def run_upgrade(cur, database_engine, *args, **kwargs):
             DROP INDEX user_filters_by_user_id_filter_id;
             DELETE FROM user_filters;
             ALTER TABLE user_filters
-               ALTER COLUMN user_id SET NOT NULL
-               ALTER COLUMN filter_id SET NOT NULL
+               ALTER COLUMN user_id SET NOT NULL,
+               ALTER COLUMN filter_id SET NOT NULL,
                ALTER COLUMN filter_json SET NOT NULL;
             INSERT INTO user_filters(user_id, filter_id, filter_json)
                 SELECT * FROM user_filters_migration;