Reduce crumbs UI in Phame live views

Summary: Makes the crumbs background and border disappear in the live view of Phame.

Test Plan: Go live, see no crumb bg. Test blog, post, mobile, desktop.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16146