Replace Esc key listeners with a CloseWatcher in supported browsers

[lukewarlow]

Currently components such as Dialogs can't be closed by platform specific close signals such as the back button / gesture on Android.

Using the new CloseWatcher API [1][2] (where supported) instead of an escape keydown event handlers would address this.

[1] https://html.spec.whatwg.org/multipage/interaction.html#the-closewatcher-interface
[2] https://developer.chrome.com/blog/new-in-chrome-120#close-watcher

https://close-watcher-demo.glitch.me/ - provides a good demo.

This would improve accessibility of primer as it would allow for screen reader users to easily dismiss primer components (close watcher supports the Talkback back gesture for example).

It would also improve consistency with the underlying platform as native html dialogs and popovers have this behaviour built in.