Kirby 4: Core Components can no longer be extended when using this plugin

[georgobermayr]

In Kirby 4, when I try to extend a core component, this is no longer possible, when using this plugin.

For instance:

"k-header": {
    extends: "k-header",
    mounted() {
        console.log("mounted my header");
    },
    template: "<div>foo</div>",
},

The template is not used. Instead the original component of Kirby is still being used.

The reason for this seems to be with the addModelWatch function in this plugin.