Fix: WindowCloseBehaviour

[Klemen2]

Closes: #3113
Fixes window not hiding for WindowCloseBehaviour:LastWindowHides,

WindowCloseBehaviour:LastWindowHides had a comment "Closing the last window will not actually close it, just hide it" but it was implemented in a way that hides all the windows so I added WindowCloseBehaviour:WindowHides that does that, and changed LastWindowHides so that it only hides on the last one, and removes the rest.

Changed multiwindow example to include tray icon & WindowCloseBehaviour:WindowHides

Temporary fix for new window not closing #3342 or at least I think that there is something else going on here and hiding the closed window is just a temporary solution to this problem since it worked in 0.5 without that.

I also changed multiwindow example to use async move, if you don't use it it gets stuck on

dioxus/packages/desktop/src/webview.rs

Line 383 in 30f760c

let webview = webview.build().unwrap();