file-based: make new methods abstract

airbyte_cdk/sources/file_based/file_based_stream_reader.py

@@ -185,16 +185,18 @@ def _get_file_transfer_paths(self, file: RemoteFile, local_directory: str) -> Li
         absolute_file_path = path.abspath(local_file_path)
         return [file_relative_path, local_file_path, absolute_file_path]
 
+    @abstractmethod
     def get_file_acl_permissions(self, file: RemoteFile, logger: logging.Logger) -> Dict[str, Any]:
         """
         This is required for connectors that will support syncing
         ACL Permissions from files.
         """
-        return {}
+        ...
 
+    @abstractmethod
     def load_identity_groups(self, logger: logging.Logger) -> Iterable[Dict[str, Any]]:
         """
         This is required for connectors that will support syncing
         identities.
         """
-        yield {}
+        ...