[#346] Fix Akkoma translations.

[blacklight]

Not sure if something has changed in the Akkoma API since the latest version of AkkomaTranslateStatus, but it seems that the API expects the target language to be lowercase (not uppercase).

Libretranslate nginx traces from my instance with the current implementation show a 400 with the current implementation:

1.2.3.4 - - [11/Feb/2025:11:40:34 +0100] "POST /translate HTTP/1.1" 400 32 "-" "Akkoma 3.13.2-0-g050bc74; https://myinstance.social <[email protected]>"

And that's also mirrored on my Akkoma logs:

1.2.3.4 - - [11/Feb/2025:11:40:35 +0100] "GET /api/v1/statuses/Ar0PZaoyJwN2GD3UJs/translations/EN HTTP/2.0" 400 54 "-" "MoshidonAndroid/2.3.0+fork.108.moshinda"

A direct API call to the endpoint above indeed returns a 400:

{"error":"libre_translate: request failed (code 400)"}

But everything works when en is used instead of EN:

{"text":"<p>Help me! </p><p>**As a large organization you go to Mastodon because: **<br/>- You want to set a standard<br/>- Guarantee your free access to your posts<br/>- as an anti-reaction against big tech and its associated:<br/> - data collections<br/> - earning models<br/> - algorithms that spread her<br/>- ... </p><p>**You run your own server because: **<br/>- your owner wants to remain over your dates<br/>- you can arrange your own accounts for your employees<br/>- ...</p><p>What arguments would you have for switching to Mastodon and own server?</p>","detected_language":"nl"}

Closes: #346