VS: Update WindowsStore support for VS 17.8
The MSVC 14.38 toolset no longer supports the /FU flag, but the
Microsoft.Cpp.AppContainerApplication.props file that comes with VS
17.8 still adds a ForcedUsingFiles by default. Add an empty
ForcedUsingFiles to work around the problem.
Fixes: #25452 (closed)
Backport: release
Topic-rename: vs-17.8-store
Edited by Brad King