R1:5cf53f7b3b42

Fix some minor curtain overflow/wrap issues

Summary:
Fixes T12503.

- 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.

Test Plan:
See T12503 for…