fix multiwindow due to mounts not dropping in virtualdom (#4351)

* fix handlers not dropping thanks to mounts

* use `desktop`

* Add tasks and effects

* only destroy on virtualdom destroy

* fix clippy

examples/window_focus.rs

@@ -8,16 +8,10 @@
 use dioxus::desktop::tao::event::Event as WryEvent;
 use dioxus::desktop::tao::event::WindowEvent;
 use dioxus::desktop::use_wry_event_handler;
-use dioxus::desktop::{Config, DefaultWindowCloseBehaviour};
 use dioxus::prelude::*;
 
 fn main() {
-    dioxus::LaunchBuilder::desktop()
-        .with_cfg(
-            Config::new()
-                .with_default_window_close_behaviour(DefaultWindowCloseBehaviour::WindowsCloses),
-        )
-        .launch(app)
+    dioxus::launch(app);
 }
 
 fn app() -> Element {