Fix italics issue with nux state on homepage

Summary: We moved to having "no data" strings render in italics, but sometimes it doesn't make sense. This renders out the panel a little more expected.

Test Plan: Clean install of Phabricator, read home page activity box.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17415