Improve error when OPENAI_API_KEY is not specified/backend is misconfigured

[tomusher]

When an OPENAI_API_KEY is not provided, or there are other configuration failures in the AI backend, triggering a rich text integration will crash the editor with no useful error messages.

These should be handled gracefully with a clearer error.

[dostogircse171]

Hi @tomusher I want to work on this issue. Any details for me?
I checked the issue and found where it's coming from. What I can see is that the issue is coming from def process(request): function of views.py we need a try-except block here before processing the request.

I will do a PR soon and if you have more information for me feel free to provide.

Thanks
-Golam