Fixed the multiple window closing issue, where the two multiwindow examples weren't working.

[sertschgi]

This was due to the tao window instance not being dropped. Furthermore the whole desktop context should have been dropped but wasn't due to the Rc that had 3 strong references too many because of copying in webview::new. I replaced everything with weak pointers so that the desktop context has 1 strong reference to the app, so that it is dropped when it is removed from the app.webviews hashmap.

Fixes #3542
Fixes #3113
Fixes #3342

[jkelleyrtp]

Thanks for the PR! I made some tweaks to track down where exactly the hardcounts are being held and then rolled in the fixes from #3466.

The hardcount increments came from a circular dependency in virtualdom -> window via the Document and WebviewEdits objects which should be fixed now.

[CryZe]

I do not believe #3542 got fixed. It still does not work on main (to be clear, the issue had nothing to do with any closing behavior, the window is broken from the start).

[Klemen2]

#3542 was not fixed since the problem is with creating a window without async in onclick events - that's why I changed the multiwindow example to use async in #3466, #3342 uses use_after_render to create a window which works.

[jkelleyrtp]

I do not believe #3542 got fixed. It still does not work on main (to be clear, the issue had nothing to do with any closing behavior, the window is broken from the start).

Ah sorry about that, I misread that issue and assumed it was a duplicate of another issue.