The comment serialization for the screenshot review UI was a bit broken,

trying to pull the wrong keys out of the serialized comment dict.
This change fixes that, and updates it so we're using our standard

region comment serialization types for everything.

Created a review request with a screenshot via the admin DB forms. Added

a comment to that screenshot and published the review. Reopened the

review UI and saw that the comment was properly loaded back into the

review UI without any errors.