Allow cache reaper to skip failing cache removal request (#45593)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/45593

I'm guessing either there is a race condition between Github removing cache entries when we're over budget OR there is an eventual consistency issue between reported cache entries and their removal.  Either way, this job is best efforts.  If a entry targetted for removal isn't there, great.

This change prevents the job from stopping if an entry no longer exists.

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D60106847

fbshipit-source-id: 252bba7bb0bbb91d279f06a39301491332cd5ace