Fix compatibility with soon to be released jupyternaut 0.1.x

[cmarmo]

Dear maintainers,
the soon to be released version of jupyternaut changes the way custom models are configured.
This pull request adds compatibility with the new configuration schema.
It fixes #37

Thank you for considering it.

NB: I couldn't find a way to retrieve the default model set in JupyterNaut as the server side configuration, eg

c.AiExtension.initial_language_model=mistral/devstral-latest

doesn't seem to have any effect on my installation.
For now I am using the first custom model of the list.
I need to investigate more on the JupyterNaut side.

[github-actions]

👈 Launch a Binder on branch cmarmo/jupyter-ai-tutor/naut-0.1

[brichet]

For the record, the change about config is in jupyter-ai-contrib/jupyter-ai-jupyternaut#70, and has been released in 0.1.0b0

[brichet]

Thanks @cmarmo for this PR.

This change seems compatible with both <0.1 and 0.1.x 👍

It looks good to me, but it may worth adding a note about this workaround. A proper solution in the long run would be to get these settings from JupyternautPersona itself I think, or to be able to set a default model.

[cmarmo]

Thanks @brichet for your review! Do you mind if I take one or two days more to understand how and if the default is set in JupyterNaut? Otherwise I will add a comment: Indeed, I don't find the current solution satisfying... 🤔