Auto-advance to the next email after a triage action

Requested via support by a power user working through large eDiscovery mailboxes, as follow-up polish to the now-shipped z/x/c triage shortcuts.

After approving / flagging / trashing an email with the new z / x / c shortcuts, the selection currently stays on the email you just actioned, so you have to press the down arrow (or click) to move on.

It would flow much better if the selection automatically advanced to the next email after an action, so you can triage straight down a list one key at a time without re-selecting each row.