The name of the custom launch image to display when your app is launched in response to the notification.
Mac Catalyst 13.0+
If you specify a value for this property, the system displays the specified image or storyboard when your app is launched because of a notification. The string in this property must match the name of an image file or storyboard in your app’s bundle. Specify nil to use the app’s default launch image. The default value of this property is nil.