fix: replace deprecated translation methods

[luka-nextcloud]

📝 Summary

• Resolves: Replace deprecated translation methods #6149

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[mejo-]

I didn't dive too deep into the changes, but a quick testing didn't work as expected. While the fake providers provided by the testing app worked, the providers provided by the translation app were not listed.

What I did to reproduce:

1. Disable app testing
2. Enable apps assistant and translate
3. Run occ translate:download-models

When I load the translation modal from the assistant menu with this PR applied, the dropdowns "translate from" and "translate to" are empty and don't provide any language. Maybe I missed something?

[luka-nextcloud]

@mejo- As I understand, the assistant app cannot work without testing app (or AI provider apps). So, disabling testing app means disabling assistant and translation. So, I think the test case doesn't make sense to me.

[juliusknorr]

There is also translate2, not sure if just an addition or successor. translate doesn't implement the new API.

@marcelklehr From an integration team perspective, is it work to keep both APIs available or is just going with the task processing API and ignoring the old translation API fine.

[luka-nextcloud]

In my opinion, we should go with the task processing API and ignore the old translation API since it might be complicated to maintain when keeping both APIs.

[marcelklehr]

We opted to implement neither forward nor backward compatibility for the old Translation API in TaskProcessing. The translate2 app only uses the TaskProcessing API, while the translate app uses the old Translation API. I'd recommend to transition to TaskProcessing directly if you don't need to support nc < 30, as the old Translation API is already deprecated and you will need to transition at some point. If it's too much work for you to add support for task processing, we can talk about adding forward and backward compatibility in server, but I'd rather avoid that.

[mejo-]

@luka-nextcloud I'm still unable to successfully test this using real translation providers. Did you test this with real providers, or just with the testing app?

What I did:

1. Disable app testing
2. 1. Setup app_api environment as documented in https://docs.nextcloud.com/server/latest/admin_manual/ai/app_api_and_external_apps.html
3. Setup translate2 app as described in https://docs.nextcloud.com/server/latest/admin_manual/ai/app_translate2.html
4. Build this branch, select something in text and open the translate assistant modal.

Problems:

• I cannot select a source language except "detect automatically"
• Selecting "translate" does nothing.

When opening the assistant modal directly in the header bar (not via Text), translation works as expected, so I guess there's something wrong with the implementation in Text.

This is how the dropdowns for selecting languages in the translation modal via Text look in my tests: