T6869, Mailing list "Public (No Login Required)" name should be visible to logged out users.

Summary: When viewing a task with a mailing list CC where the mailing list is public, logged out user should see the name of the mailing list

Test Plan: Create public mailing list, CC mailing list on task, logout and view task, mailing list name should still be visible on the task

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11290