Test language with a different reading direction

Test done, it does not work.

https://drupal.slack.com/archives/C1BMUQ9U6/p1751445615235749

Currently there is no API in Core to handle that automatically.

So either in a first time do workarounds in ui_suite_bootstrap, or start directly with a Core issue to add support.

https://github.com/twbs/bootstrap/issues/38024