Fix for Ungrouped Bug

Current behaviour:
* Ungrouped group management gives errors in languages that have it translated.

Summary of changes:
* Prevent "Ungrouped" being translated in the URL and as the group_id
* Add a test to check that "Ungrouped" will always display without error in Spanish, which has shown the bug most frequently.
Nevermind, saw the discussion on Hipchat.