Applying Composition translation on a FrameworkElement that also sets facade properties breaks hit testing

Nobody has claimed this yet.

### Describe the bug

If you sets a `Translation` on a `FrameworkElement` in xaml, something like this:
```xml

```
And you try to get its backing `Visual` and translate it in code
```cpp
auto visual = winrt::Microsoft::UI::Xaml::Hosting::ElementCompositionPreview::GetElementVisual(Source());
auto compositor = visual.Compositor();
if (translation)
{
translation.Direction(winrt::Microsoft::UI::Composition::AnimationDirection::Reverse);
visual.StartAnimation(L"Translation.XY", translation);
}
else
{
winrt::Microsoft::UI::Xaml::Hosting::ElementCompositionPreview::SetIsTranslationEnabled(Source(), true);
translation = compositor.CreateVector2KeyFrameAnimation();
translation.InsertKeyFrame(0.0f, { 0.f, 0.f });
translation.InsertKeyFrame(1.0f, { 20.f, 20.f });
visual.StartAnimation(L"Translation.XY", translation);
}
```
It will break the hit testing quietly.

Doing the same thing in UWP you will get an exception
```
WinRT originate error - 0x80070005 : 'Access denied. Calling ElementCompositionPreview.GetElementVisual API is not allowed on this object at this time, as this object currently has the Translation property in use.'
```

### Why is this important?

This lacks of documentation is actually dated back to #4904 on UWP (which is 4+ years old btw), and is still not documented on winui3. And now the issue is even more obscure, as no errors get printed, but hit testing is broken.

### Steps to reproduce the bug

As OP.

### Actual behavior

_No response_

### Expected behavior

_No response_

### Screenshots

_No response_

### NuGet package version

WinUI 3 - Windows App SDK 1.8.3: 1.8.251106002

### Windows version

Windows 11 (24H2): Build 26100, Windows 10 (1809): Build 17763

### Additional context

_No response_

Start by checking the documentation for ElementCompositionPreview.GetElementVisual and SetIsTranslationEnabled against the XAML/C++ reproduction in this issue. Done when the relevant API guidance explains the interaction with the FrameworkElement Translation property, including the hit-testing consequence and the supported alternative.

Written by the indexing model from the issue text.