MenuFlyout with cascading menus has weird shadow

[HO-COOH]

Describe the bug

As title suggest. It looks exceptionally bad if the app is using a dark theme, but shown on a white background.

Steps to reproduce the bug

1. Go to MenuFlyout page in winui 3 gallery
2. Click to open the "A MenuFlyout with cascading menus" sample

Expected behavior

No response

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.5.3: 1.5.240428000

Windows version

Windows 10 (1809): Build 17763

Additional context

No response

[github-actions]

Hi I'm an AI powered bot that finds similar issues based off the issue title.

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one. Thank you!

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• MenuFlyout DropShadow persists after it is dismissed (#9485), similarity score: 0.78

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