Transparent window is not working on macOS with 11.0.0-preview5

[carina-studio]

Describe the bug
Setting Window.TransparencyLevelHint to Transparent seems not working on macOS with 11.0.0-preview5. The Window background is still there no matter setting Background to null or transparent. Popups with CornerRadius are also affected by this issue, there will be a visible rectangle background under the popup which should not be there. It works fine with 11.0.0-preview4.

To Reproduce

1. Set Window.TransparencyLevelHint to Transparent.
2. Set Window.Background to null or transparent.
3. Check the window.

Expected behavior
No window background when setting TransparencyLevelHint to Transparent and set Background to null or transparent.

Screenshots

**Desktop

• OS: macOS 13.2
• Avalonia Version 11.0.0-preview5
• .NET Version: 7

Additional context
N/A

[maxkatz6]

It was fixed in current master. Broken in preview5.
#10196