Cache application visibility in the request cache

Summary: Ref T8575. We check if users can see applications frequently, and caching on the Query isn't especially effective. Use the new Request cache instead.

Test Plan:

• Saw /feed/ drop 7% (from ~830ms to ~770ms) on profiles.

Reviewers: btrahan, avivey

Reviewed By: avivey

Subscribers: avivey, epriestley

Maniphest Tasks: T8575

Differential Revision: https://secure.phabricator.com/D13321