[code review] Do not publish comments immediately on approval

I tried using Review Helper recently, and one thing I noticed was that as soon as approve a proposed review comment, it gets published immediately. As a result, Phabricator will generate a separate notification email for every Review Helper comment (and these will be in addition to the notification email sent for any review comments I write manually).

I would rather that approved comments be "unsubmitted", similar to when I write a comment manually, and then submitted in a single batch (triggering a single notification for my patch author) when I submit my review.