WeakReferenceList behavior maybe no safe

This is the code.

https://github.com/dotnet/wpf/blob/87115e5b0efade5ec32379264e9909d11b01a9e4/src/Microsoft.DotNet.Wpf/src/Shared/MS/Internal/WeakReferenceList.cs#L187-L189

And as we can see, the code check the WeakReference is alive and then get the Target. But the GC will collect the object before we get the Target and after we check the IsAlive.

And I think we should use the TryGetTarget to get the value.

Thank you.