[wayland labwc] applets don't auto-close on lost focus (potential solution)

Wisker menu maintainer seem to have found the solution for auto closing applet/menu windows when they lose focus:

panel-plugins/xfce4-whiskermenu-plugin#150 (comment 99255)

Opening this here so that applets like battery or calendar/time can use it too. They seem to rely on Xfce panel for handling GtkLayerShell