service_api: suppress traceback for ServiceAuthError in _gather

room_cal/service_api/client.py

@@ -116,7 +116,7 @@ class ServiceAPI:
     out: dict[str, object] = {}
     for key, result in zip(keys, raw):
       if isinstance(result, BaseException):
-        _log.error('service %s error (skipping): %s', key, result, exc_info=result)
+        _log.error('service %s error (skipping): %s', key, result, exc_info=not isinstance(result, ServiceAuthError))
         out[key] = None
       else:
         out[key] = result