Investigate single-locale language repacks for Tor Browser on desktop
Right now we ship in every non en-US bundle both the en-US locale and a language pack for the respective locale. We can do better here by doing the "single-locale language repacks-trick" (https://searchfox.org/mozilla-central/source/build/docs/locales.rst). This would not only save some bundle size but would help us as well routing around the signature problem we have with the signed language packs (see: #26465 (moved)).