Fix a case where "Accept + Comment" would ignore the "Accept"

Summary:
Ref T11114. When you comment, we try to upgrade your review status to "commented".

This can conflict with upgrading it to "accepted" or "rejected", or removing it entirely.

For now, just avoid making this update. After T10967, I expect "you commented" to be orthogonal to accepted/rejected so it should stop conflicting on its own.

Test Plan:

• As an "added" reviewer, accepted a revision with a comment in the same transaction.
• Before patch: accept didn't stick.
• After patch: accept sticks.

This may be somewhat magical/order-dependent but I was able to reproduce it locally.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11114

Differential Revision: https://secure.phabricator.com/D17146