Now that admins can make a choice about whether they want to view an

unpublished draft or not, we need to be more careful about when they

make edits. This change makes it so if the admin attempts to make a

change to the review request when a user draft exists, we'll block the

edit and prompt them to load the draft first.

Attempted to edit review request fields, file attachment

  captions/state, and add new attachments/diffs as an admin while

  viewing a review request with an unpublished draft, but not viewing

  the draft. Saw the expected prompt.
Edited review request fields, file attachment captions/state, and

  added new attachments/diffs as both the owner and an admin while

  viewing the current draft.