Add missing API paths + request bodies to `openapi.yml`

You wrote at #3466555-26: Also validate request bodies against the OpenAPI spec → that

Can you create a follow-up issue to document the routes that do not yet have request bodies documented in openapi.yml? 🙏 (i.e. for the @todo that @tedbow commented on over at https://git.drupalcode.org/project/experience_builder/-/merge_requests/2...)

was addressed by 🐛 OpenAPI validation errors must be provided as a JSON response RTBC , but it is not.

I think it makes sense to do that as part of this issue?

I think it makes sense to do that as part of this issue?

Yes, that's what this issue is for. I just copy/pasted the wrong issue link in the other comment.

👍 Great, ignore my comment then! 😅