We originally needed this library (or a separate DLL in our own project)
to handle hooking up the XAML resource loader to the providers that our
application needed. It was introduced in its nascent form in 2019, in a
PR titled "Make XAML files work."
It appears we no longer need it, and the provider hookup is being
handled by our `AppT2` base class override. I've tested this in Windows
10 Vb running unpackaged, and it seems to work totally fine. Crazy.
Removing this dependency saves us a couple hundred kilobytes on disk and
removes one consumer of the App CRT from our package.
68cce101bc