CI/windows: Update headers and Agility redist to 1.710.0-preview
The new headers include several new features we'd like to use in Dozen. Since this is a preview Agility SDK release, the version tag in DirectX-Headers isn't updated, so we can't require these headers, but at least let's start using them to clean up Dozen's CI fail expectations. I'll make those changes separately though since this MR will require running CI for all drivers...