Fix discarding review request drafts.
Review Request #15034 — Created May 8, 2026 and submitted — Latest diff uploaded
The actions rework added an assertion before we show the confirmation
dialog for discarding review request drafts, but the logic here was
backwards. This was checking whether the draft object exists on the
server and then saying that there was draft to discard.
Created a review request with a draft update and was able to discard
that draft.