Add proper null checking

Author: keveleigh

Assets/MixedRealityToolkit.Providers/WindowsMixedReality/XR2018/WindowsMixedRealityArticulatedHand.cs

@@ -227,7 +227,14 @@ private void UpdateHandData(InteractionSourceState interactionSourceState)
                     HandPose handPose = sourceState.TryGetHandPose();
 
 #if WINDOWS_UWP
-                    if (CoreServices.InputSystem.InputSystemProfile.HandTrackingProfile.EnableHandMeshVisualization)
+                    MixedRealityHandTrackingProfile handTrackingProfile = null;
+                    MixedRealityInputSystemProfile inputSystemProfile = CoreServices.InputSystem?.InputSystemProfile;
+                    if (inputSystemProfile != null)
+                    {
+                        handTrackingProfile = inputSystemProfile.HandTrackingProfile;
+                    }
+
+                    if (handTrackingProfile != null && handTrackingProfile.EnableHandMeshVisualization)
                     {
                         // Accessing the hand mesh data involves copying quite a bit of data, so only do it if application requests it.
                         if (handMeshObserver == null && !hasRequestedHandMeshObserver)

Assets/MixedRealityToolkit.Providers/WindowsMixedReality/XRSDK/Controllers/WindowsMixedRealityXRSDKArticulatedHand.cs

@@ -158,7 +158,14 @@ private void UpdateHandData(InputDevice inputDevice)
             }
 
 #if WINDOWS_UWP
-            if (!CoreServices.InputSystem.InputSystemProfile.HandTrackingProfile.EnableHandMeshVisualization)
+            MixedRealityHandTrackingProfile handTrackingProfile = null;
+            MixedRealityInputSystemProfile inputSystemProfile = CoreServices.InputSystem?.InputSystemProfile;
+            if (inputSystemProfile != null)
+            {
+                handTrackingProfile = inputSystemProfile.HandTrackingProfile;
+            }
+
+            if (handTrackingProfile == null || !handTrackingProfile.EnableHandMeshVisualization)
             {
                 // if hand mesh visualization is disabled make sure to destroy our hand mesh observer if it has already been created
                 if (handMeshObserver != null)