Fix some minor curtain overflow/wrap issues
- Users with creative usernames like MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM could overflow "Subscribers" in the curtain UI.
- Other content like packages could also overflow.
- Users with interesting and unique names like WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW who were also away or disabled could get a linebreak between their availability dot and their username.
See T12503 for "before" screenshots. Also tested mobile, which looked fine, but didn't screenshot it.
Reviewed By: chad
Maniphest Tasks: T12503
Differential Revision: https://secure.phabricator.com/D17650