don't update tracking state on device change before initialisation

Author: ritamerkl

Packages/com.unity.inputsystem/InputSystem/Plugins/XR/TrackedPoseDriver.cs

@@ -499,6 +499,8 @@ protected void UpdateCallback()
 
         void OnDeviceChanged(InputDevice inputDevice, InputDeviceChange inputDeviceChange)
         {
+            if (m_IsFirstUpdate)
+                return;
             ReadTrackingStateWithoutTrackingAction();
         }