Localize more user facing strings

[jtpio]

Problem

Briefly looking at the code, it looks like there are a couple more strings could be localized using the JupyterLab translator, for example:

jupyter-chat/packages/jupyterlab-collaborative-chat/src/index.ts

Line 341 in f3ba6e0

label: 'Open a chat',

Proposed Solution

Use the ITranslator in more places.

[brichet]

@jtpio would it be enough to use the ITranslator ?
Don't we have to provide also the translations for each sentence somewhere (i.e. in language packs directly) ?

[jtpio]

Yes it's enough to just use the ITranslator for the extension code itself 👍

But I think we also need to add it to this repo: https://github.com/jupyterlab/language-packs?tab=readme-ov-file#adding-a-new-extension, so it can be integrated in the translation process via crowdin.

When using the translator in the extension, we can then use the name of the extension, for example:

translator.load('jupyter-chat')