[SG-823] Undid changes to capture device push token on login (#2427)

* Revert "Set Id property on existing devices so we don't try to create a new one instead of updating existing. (#2420)"

This reverts commit 02e4b10ae8.

* Revert "Update push token on login to allow multiple users on mobile devices (#2404)"

This reverts commit 24469e2267.

* Added back test changes.

src/Core/Services/IDeviceService.cs

@@ -7,5 +7,4 @@ public interface IDeviceService
     Task SaveAsync(Device device);
     Task ClearTokenAsync(Device device);
     Task DeleteAsync(Device device);
-
 }