R1:f7d975ab722d

Fix refresh profile picture functionality

Summary:
turns out both github and Phabricator fall back to if the user already has a login session when accessing the pertinent profile picture data. Facebook on the other hand is a stingy bastard about have an actual access token. Ergo, in production (once I could test Facebook) this button failed.

The patch sets the access token properly such that the provider can use it properly when retrieving the profile image.

Test Plan: re-did my meta-Phabricator test…