Post a single PR Review with a body

[strawgate]

See: elastic/ai-github-actions#5

The workflow posts each pr review comment as its own PR review and doesn't have the ability to post an actual review status like "Approved" or "Request Changes".

We should collate all of the comments into one PR Review and then we should give the ability for the agent to set the review state as Approved, Request Changes, or Comment.

[pelikhan]

Yes inded. I had overlooked that this API support both the review state and a set of comments.