All Xbox controller's dpad does not work on UWP.

Repro:
1. Download package and project: https://github.com/Unity-Technologies/InputSystem
2. Build UWP player for Input Test (Assets -> QA -> Input_Test -> Scenes)
3. Use the drop-down menu on the top to switch to Xbox
4. Connect a Xbox controller and observe

Actual: The dpad does not work.

Note: this happens to all kinds of xbox controller, including 360 and Xbone, wired or wireless.