C++: Can't `UnloadObject` after removing it from visual tree

### Describe the bug

I get an exception if I Unload an object after having removed from the visual tree.

This is only an issue in C++. I could not reproduce this in C#.

Is there a work around?

### Steps to reproduce the bug

```xaml

Click Me

```

```cpp
void MainWindow::myButton_Click(IInspectable const&, RoutedEventArgs const&)
{
myStackPanel().Children().ReplaceAll({ myButton() });
UnloadObject(myButton());
}
```

> Microsoft.UI.Xaml.dll!00007FF60A67D0F3: 80070057 - E_INVALIDARG
Exception thrown at 0x00007FF881B12BDC (KernelBase.dll) in App2.exe: WinRT originate error - 0x80070057 : 'The parameter is incorrect.'.
Exception thrown at 0x00007FF881B12BDC in App2.exe: Microsoft C++ exception: winrt::hresult_invalid_argument at memory location 0x00000038262F9FD8.
Exception thrown at 0x00007FF881B12BDC in App2.exe: Microsoft C++ exception: [rethrow] at memory location 0x0000000000000000.
A breakpoint instruction (__debugbreak() statement or a similar call) was executed in App2.exe.

### Expected behavior

_No response_

### Screenshots

_No response_

### NuGet package version

WinUI 3 - Windows App SDK 1.6.2: 1.6.241106002

### Windows version

Windows 11 (21H2): Build 22000

### Additional context

_No response_

Reproduce the issue using the provided XAML and C++ click handler with Windows App SDK 1.6.2 on Windows 11. Compare removing myButton with ReplaceAll followed by UnloadObject against the C# behavior; done means the C++ path no longer raises E_INVALIDARG or has a documented, working resolution.

Written by the indexing model from the issue text.