Prevent update bubbles when resolving/reopening issues.

When resolving or reopening an issue, the code was marking the review
request as updated, using the timestamp coming from the response.
However, this timestamp wasn't actually factored into the review
request's last activity timestamp, so it ended up popping up an update
bubble showing the actual previous update.

That code is just gone now. There's no longer any update bubbles when
resolving issues.