fix missing declaration

Author: aaronsteers

airbyte_cdk/test/standard_tests/connector_base.py

@@ -44,6 +44,7 @@ def connector(cls) -> type[IConnector] | Callable[[], IConnector] | None:
         This assumes a python connector and should be overridden by subclasses to provide the
         specific connector class to be tested.
         """
+        connector_root = cls.get_connector_root_dir()
         connector_name = cls.connector_name
 
         expected_module_name = connector_name.replace("-", "_").lower()