Update potential duplicates filter to show only unconfirmed tickets

Tickets may show up as potential duplicates after the confirmation status has been changed from "unconfirmed." Tickets that are not unconfirmed are probably not duplicates. Can we add the following to the end of that filter:

... and "Confirmation Status" = unconfirmed

This will save mods the trouble of looking for confirmation status in potential duplicates and setting CHK accordingly.