fdo#61251 prefer exact matches before case guess matching

Change-Id: I3a7badf063110e78d53859381efba32837aa71bb
convert sepia dialog to .ui

Change-Id: I6032ea0da029e5bff145e582892655143400f710
convert posterize dialog to .ui

Change-Id: If21e85cd0802c9f1b2bd244e6fb3715bef395e0a
convert mosaic dialog to .ui

Change-Id: Ibc723ca79fba89f24e04440fdbf4140a4e0655ad