Fix mypy potential issue if no secrets toml loaded

src/login.py

@@ -21,6 +21,9 @@ class HFFriendlyGSheetsConnection(GSheetsConnection):
         if secrets_singleton.load_if_toml_exists():
             connections_section = AttrDict(secrets_singleton)
 
+        if connections_section is None:
+            return AttrDict({})
+
         connections_copy = connections_section.to_dict()
         # in hf env the private key may need json loads
         private_key = connections_copy["private_key"]