ModalDialog.extend broken since 4.1.5

[bjornharrtell]

I suspect internal rewrite to glimmer component (#406) might be the cause.

[saracope]

I'm also seeing this error. Is there a planned fix?

[lukemelia]

Now that the dialog HTML element is widely supported, I'm not actively maintaining this addon. I'm open to PRs to fix this and am happy to review and merge.