Skip loading attached objects for files when we know the file is visible

Summary:
Depends on D19222. Ref T13106. We currently execute an edge query (and possibly an object query) when loading builtin files, but this is never necessary because we know these files are always visible.

Instead, skip this logic for builtin files and profile image files; these files have global visibility and will never get a different policy result because of file attachment information.

(In theory, we could additionally skip this for files with the most open visibility policy or some other trivially visible policy like the user's PHID, but we do actually care about the attachment data some of the time.)

Test Plan: Saw queries drop from 151 to 145 on local test page. Checked file attachment data in Files, saw it still working correctly.

Maniphest Tasks: T13106

Differential Revision: https://secure.phabricator.com/D19223