Bug fix for diffusion browse views for images and binary files

Summary: D3499 introduced some new hotness but broke these less common cases. add slightly updated ui for this. Note we need a 'download' icon for this UI to not be horrendous.

Test Plan: viewed a binary file and an image in diffusion browse view

Reviewers: epriestley

Reviewed By: epriestley

CC: nh, aran, Korvin

Maniphest Tasks: T1997

Differential Revision: https://secure.phabricator.com/D3849