tests: fix CI and translation tests

[kcaran]

Updated the Github CI to use Ubuntu 24.04 correctly. The translation tests needed the $LANG environmental variable set and and the date regular expressions needed the /u UTF-8 flag. I also included PHP 8.3 and 8.4 and remove 7.4 and 8.0.

[kcaran]

I wrote up how I debugged the Github Actions: https://www.kcaran.com/posts/debugging-github-ci-actions.html

[nodiscc]

a w e s o m e
Thank you, and great writeup on the debugging process

I don't know this env variable was named UT_LOCALE in the first place, I can't find any reference to this name anywhere. In hindsight LANG is obviously correct.

The change to non-breaking spaces was tricky, @thican also had identified it in #2120, so thank you both.

The tests breaking all of a sudden means we have a dependency that is not properly pinned somewhere (I suspect the stray composer update in the test suite has something to do with it), will deal with this in a separate PR.

You just need to re-enable all php versions in the test matrix ^ comment above