Show timestamps all the time in Conpherence

Summary: Fixes T9112. These got removed accidentally at some point. Add them back.

Test Plan: Visit a Conpherence, desktop, mobile, web, column.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T10364, T9112

Differential Revision: https://secure.phabricator.com/D16534