Fix launchers getting lost on DND resorts when using 5.6-style config.

This is an unfortunate regression that crept in via 7eff45a98f the
just the other day: Legacy config can have query items other than
iconData in launcher URLs, which also need to be stripped before doing
the equivalence test matching up launcher-backed window tasks with
launcher URLs. Back to venerable launcherUrlsMatch() as originally --
the real speed optimization is in fetching the right role, anyway, and
as it turns out we really can't save that one call to adjusted() as it
was necessary.

BUG:364492

libtaskmanager/tasksmodel.cpp

@@ -1415,8 +1415,7 @@ void TasksModel::syncLaunchers()
         for (int i = 0; i < rowCount(); ++i) {
             const QUrl &rowLauncherUrl = index(i, 0).data(AbstractTasksModel::LauncherUrlWithoutIcon).toUrl();
 
-            // RemoveQuery to strip possible fallback icon from stored launcher.
-            if (launcherUrl.adjusted(QUrl::RemoveQuery) == rowLauncherUrl) {
+            if (launcherUrlsMatch(launcherUrl, rowLauncherUrl, IgnoreQueryItems)) {
                 row = i;
                 break;
             }