ContentDialog missing radius on bottom corners in Light mode when IsFooterVisible=False

[oklahsam]

Describe the bug

When showing a content dialog with IsFooterVisible=False, the bottom corners are missing the radius (not rounded) in the Light mode theme.

To Reproduce

Create a content dialog, either in XAML or using the ContentDialogService, and set IsFooterVisible=False. Then switch between Light and Dark mode to see the difference.

Expected behavior

The bottom corners of the ContentDialog should be rounded in Light mode like they are in Dark mode.

Screenshots

Light Mode:

Dark Mode:

OS version

Windows 11 Pro (23H2, build 22531.4602)

.NET version

.NET 8

WPF-UI NuGet version

WPF-UI 3.0.5

Additional context

No response