Accessing NonClientRegionsChangedEventArgs.ChangedRegions with AOT enabled causes NotSupportedException

Describe the bug

When NativeAOT is enabled, accessing NonClientRegionsChangedEventArgs.ChangedRegions in my InputNonClientPointerSource.RegionsChanged event handler, it throws System.NotSupportedException with message "Cannot handle array marshalling for non blittable type 'Microsoft.UI.Input.NonClientRegionKind'.". But it works properly without NativeAOT.

Why is this important?

• Non-client regions set by InputNonClientPointerSource.SetRegionRects will become 0×0 rects unexpectedly, for example, when the title bar area set by Window.SetTitleBar and InputNonClientPointerSource.SetRegionRects with NonClientKind.Caption dragged and clicked. It is also mentioned at #10379 . Handling InputNonClientPointerSource.RegionsChanged event is a feasible way to remedy this issue.
• NativeAOT is a good feature.

Steps to reproduce the bug

1. Create a new C# WinUI 3 project.
2. Enable "Publish Native AOT" in the project property settings.
3. Handle InputNonClientPointerSource.RegionsChanged event and access NonClientRegionsChangedEventArgs.ChangedRegions.

public sealed partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        ExtendsContentIntoTitleBar = true;
        _inputNonClientPointerSource = InputNonClientPointerSource.GetForWindowId(AppWindow.Id);
        _inputNonClientPointerSource.RegionsChanged += OnNonClientRegionsChanged;
    }

    private void OnNonClientRegionsChanged(InputNonClientPointerSource sender, NonClientRegionsChangedEventArgs args)
    {
        NonClientRegionKind[] changedRegions = args.ChangedRegions;
    }

    private readonly InputNonClientPointerSource _inputNonClientPointerSource;
}

Actual behavior

System.NotSupportedException is thrown at NonClientRegionKind[] changedRegions = args.ChangedRegions with message: "Cannot handle array marshalling for non blittable type 'Microsoft.UI.Input.NonClientRegionKind'".

Expected behavior

Cause no exceptions.

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.8.1: 1.8.250916003

Windows version

Windows 11 (24H2): Build 26100

Additional context

No response

Reproduce the issue in a C# WinUI 3 project using the Native AOT setting, then follow the InputNonClientPointerSource.RegionsChanged handler and NonClientRegionsChangedEventArgs.ChangedRegions access described here. Investigate the array marshalling path for NonClientRegionKind; done means accessing ChangedRegions causes no NotSupportedException under Native AOT and the existing behavior remains intact without it.