Removing broken part of monitors example

This worked on at least one platform at some point in time, but it
appears that at least with the current winit, the extra example would
always lead to an event loop error.

examples/monitors.rs

@@ -1,12 +1,10 @@
 use cushy::kludgine::app::{Monitor, Monitors};
 use cushy::widget::{MakeWidget, WidgetInstance, WidgetList};
-use cushy::{Application, Open, PendingApp};
+use cushy::Open;
 
 fn main() -> cushy::Result {
     // Monitor information is only available through winit after the application
     // has started up.
-    assert!(PendingApp::default().as_app().monitors().is_none());
-
     cushy::run(|app| {
         let monitors = app.monitors();