Describe the bug

ListDetailsView causes hard crash in normal usage.

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:
  7.0.1

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Create a WinUI3/WAS project, install toolkit 7.1.1-preview3
2. Add a ListDetailsView, set ListPaneWidth and some content
3. if ListPaneWidth set in xaml, it will fail with XamlParseException which wrappes NullReferenceException
   4. When moving mouse over the control. it will fail with not being able to load reveal brush
   Edit: I used reveal brush in my custom style. It's not caused by the control itself.

Environment

NuGet Package(s):
CommunityToolkit.WinUI.UI.Controls.Layout
Microsoft.WindowsAppSDK 1.0.0-preview3

Package Version(s):
7.1.1-preview3

Windows 10 Build Number:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19043)
• Insider Build ({build_number})

App min and target version:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)
• Insider Build ({build_number})

Device form factor:

• Desktop
• Xbox
• Surface Hub
• IoT

Visual Studio version:

• 2017 (15.{minor_version})
• 2019 (16.{minor_version})
• 2022 (17.{minor_version})

Additional context

This could be a issue of WinUI side, but we should be aware of them here.