Support Mistral Chat

[ElYaiko]

I see at the moment only the Mistral FIM is supported but Mistral Chat ( https://codestral.mistral.ai/v1/chat/completions ) is not supported.

I'm using custom actions with Helix so it would be useful to support Mistral Chat so custom instructions (prompt) can be passed in the parameters (ex: To Refactor).

Thanks.