qmlui: enable context menu entry hover only when visible
qmlui: enable context menu entry hover only when visible

This fixes an annoying highlight issue in the action menu

sbenejam/qlcplus,mcallegari/qlcplus,kripton/qlcplus,kripton/qlcplus,sbenejam/qlcplus,kripton/qlcplus,plugz/qlcplus,sbenejam/qlcplus,kripton/qlcplus,plugz/qlcplus,mcallegari/qlcplus,plugz/qlcplus,mcallegari/qlcplus,plugz/qlcplus,plugz/qlcplus,sbenejam/qlcplus,kripton/qlcplus,sbenejam/qlcplus,plugz/qlcplus,sbenejam/qlcplus,kripton/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,kripton/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,plugz/qlcplus