ci: Fix wording on stale bot for Author Feedback

Summary:
Fix wording to make it clear that the issue / PR is marked stale because of inaction.
Changelog:
[Internal] - Fix wording that was meant to go in on D42531703 (https://github.com/facebook/react-native/commit/474c0edafea6d8fad4874a22bfd777bacf30a1f7)

Reviewed By: cortinico

Differential Revision: D42547980

fbshipit-source-id: 01e624ae66348d2528fa1f5bbbc2aacb24ddd865