improve error message when AI prompt rate is exceeded
Context
Result from #926 (closed) -- see note_136279
Proposal
Improve error message for Code 429 which means we had reached the Rate limit for requests to OpenAI https://help.openai.com/en/articles/6891829-error-code-429-rate-limit-reached-for-requests
Rate Limit Exceeded
It looks like you’ve made too many requests in a short period. We have usage limits to ensure service reliability. Please wait for a few minutes before trying again.
If you’re repeatedly getting this message, please contact your admin.