App crashes when clearing ObservableCollection

### Describe the bug

Clearing an `ObservableCollection` can cause this exception in certain cases (perhaps when page is unloaded and garbage collected):

`System.Runtime.InteropServices.COMException: Unspecified error`

### Steps to reproduce the bug

Download and run this example project: [Test.zip](https://github.com/user-attachments/files/18752216/Test.zip)

### Expected behavior

No crash

### Screenshots

_No response_

### NuGet package version

WinUI 3 - Windows App SDK 1.6.3: 1.6.241114003

### Windows version

Windows 11 (24H2): Build 26100

### Additional context

Related bug reports:
https://github.com/microsoft/microsoft-ui-xaml/issues/8684
https://github.com/microsoft/microsoft-ui-xaml/issues/7639
https://github.com/CommunityToolkit/Windows/issues/616

Start by downloading and running the attached Test.zip on Windows 11 with Windows App SDK 1.6.3, then inspect the clearing and page-unload scenario that produces the COMException. Compare the behavior with related issues 8684, 7639, and 616; done means clearing the ObservableCollection no longer crashes.

Written by the indexing model from the issue text.