Add support for GNOME 46

[sidt4]

Fails with the following error in Gnome 46.0.

Mar 21 18:32:56 linux gnome-shell[22033]: Extension [email protected]: TypeError: this.layoutManager.add is not a function

       Stack trace:
	 enable@file:///home/sid/.local/share/gnome-shell/extensions/[email protected]/extension.js:222:28
	 _callExtensionEnable@resource:///org/gnome/shell/ui/extensionSystem.js:266:38
	 loadExtension@resource:///org/gnome/shell/ui/extensionSystem.js:478:32
	 async*reloadExtension@resource:///org/gnome/shell/ui/extensionSystem.js:526:20
	 async*_onVersionValidationChanged@resource:///org/gnome/shell/ui/extensionSystem.js:672:24
	 async*_loadExtensions/<@resource:///org/gnome/shell/ui/extensionSystem.js:740:18
	 @resource:///org/gnome/shell/ui/init.js:21:20

Gnome 46 upgrade reference:

https://gjs.guide/extensions/upgrading/gnome-shell-46.html