Remove errant wedgies in timeline

Summary: The removes the wedge until such time as we have Herald/Build icons. Actually, this is probably better/cleaner.

Test Plan: Have Herald add me as a CC, test new layout in desktop and mobile.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D8895