DeepL glossary missing Arabic as source and target language

The language Arabic is not supported by the API for now.
Available languages are listed here: https://developers.deepl.com/docs/api-reference/glossaries/openapi-spec-...

Once the language is available via the API, i'll update the tmgmt_deepl_glossary submodule.

I made a GET request to the https://api.deepl.com/v2/glossary-language-pairs endpoint. While the response included multiple language pairs, I'm only including the English to Arabic pair:
{
"supported_languages": [
{
"source_lang": "en",
"target_lang": "ar"
}
]
}
Thank you for looking at this. :)

Thank you once again for taking care of this, but the merge failed due to phpcs and phpstans :(

@sachit.thapa: The tests for phpstan (next minor) won't be fixed for the 2.2.x release.
Those are handled in 2.3.x - were all pipelines are green.

It would be great, if you could test the Merge Request with version 2.2.x on you projects and provide feedback. Afterward i'll integrate the feature into 2.3.x.