Admins, when Viewing As, should see the pseudo-user's last log-in status in the view-as footer

https://jira.ets.berkeley.edu/jira/browse/CLC-3487

Works visually with UIDs referenced in the Jira.

The integration test only guarantees that the correct messages
exist in the template because the html body return only contains
the unrendered angularjs template.
Merge pull request #2321 from chikoon/CLC-3487-see-viewed-as-last-login-in-footer

Admins, when Viewing As, should see the pseudo-user's last log-in status in the view-as footer