Mark text as not translatable in UI files

[ann0see]

If this is the case, we might want to update a few more ui files and mark text as not translatable to minimize translation effort. What do you think?

Probably worth a separate issue for 3.10.0 but yes.

For now, this can be left as is, as it's not used.

Originally posted by @pljones in https://github.com/jamulussoftware/jamulus/pull/2835#discussion_r964166516

[pljones]

No one assigned. No progress. Dropping milestone and moving back to Triage.