[ticket/11103] Correct the test case

Fix a bug that broke it and make sure to set the needed config/auth settings

PHPBB3-11103

tests/mock/notifications_auth.php

@@ -32,4 +32,9 @@ class phpbb_mock_notifications_auth extends phpbb_auth
 
 		return $auth_list;
 	}
+
+	function acl_get($opt, $f = 0)
+	{
+		return true;
+	}
 }