Add 4XX descriptions for the following resources

[jaeyson]

Change Summary

Hi! First off thank you for creating this great spec file. I'm using the open api spec for generating an API client.

Adding 4XX descriptions for the following:

• GET and DELETE for /conversations/models/{modelId}:
• GET for /collections/{collectionName}/overrides:
• GET for /collections/{collectionName}/overrides/{overrideId}:
• DELETE for /collections/{collectionName}/documents:
• POST for /analytics/rules:

It helps me pass the unit tests, as it's missing in the current spec file. Is it possible to add this descriptions?

PR Checklist

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