Alien Cake Addict example: don't exit when player lose (#8388)

# Objective

- Example Alien Cake Addict exit when the player lose, it's not supposed
to

## Solution

- Don't despawn the window

---------

Co-authored-by: ira <JustTheCoolDude@gmail.com>

examples/games/alien_cake_addict.rs

@@ -182,8 +182,8 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>, mut game: ResMu
     );
 }
 
-// remove all entities that are not a camera
-fn teardown(mut commands: Commands, entities: Query<Entity, Without<Camera>>) {
+// remove all entities that are not a camera or window
+fn teardown(mut commands: Commands, entities: Query<Entity, (Without<Camera>, Without<Window>)>) {
     for entity in &entities {
         commands.entity(entity).despawn();
     }