[applets/kicker] Fix missing highlight on Dashboard grids & list
Part of the reason was incomplete PlasmaExtras.Highlight refactoring, other part is anchors not working for highlight instance:
/usr/share/plasma/plasmoids/org.kde.plasma.kicker/contents/ui/DashboardRepresentation.qml:970:36:
QML Highlight: Cannot anchor to an item that isn't a parent or sibling.