Sometimes can't open a new window by "Open in New Window"

[kkebo]

Steps to reproduce:

1. Close all windows of DevToys
2. Open DevToys
3. Go back to the home screen
4. Go back to the DevToys app from the Dock
5. Open the context menu on the sidebar or the "All Tools" screen
6. Select "Open in New Window"

https://user-images.githubusercontent.com/601636/235153525-b2e81f7a-6ff7-4729-af77-9a4c18afb351.mov

Expected behavior:

A new window will be opened.

Environment;

• iPad Pro 12.9-inch 6th generation
• iPadOS 16.5 (20F5050f)

[kkebo]

Solutions:

• Add a plain WindowGroup as the default window group
• Use UIApplication.shared.requestSceneSessionActivation to open a new window instead of openWindow