Don't show Conpherence controls if not in a Conpherence

Summary: We currently try to build crumbs out even if the user has no membership in any. This removes these useless controls.

Test Plan: Leave all Rooms, see NUX state with no "Edit Room", blank title, or "Collapse Column" controls.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16546