Merge branch 'latest-preview' into light-estimation

Assets/Scenes/FaceTracking/DisplayFaceInfo.cs

         {
             m_FaceManager = GetComponent<ARFaceManager>();
             m_Session = GetComponent<ARSession>();
-            m_CameraManager = GetComponent<ARSessionOrigin>().camera?.GetComponent<ARCameraManager>();
+            var camera = GetComponent<ARSessionOrigin>().camera;
+            m_CameraManager = camera ? camera.GetComponent<ARCameraManager>() : null;
         }
 
         void OnEnable()
             // Detect face tracking with world-facing camera support
-            var subsystem = m_Session?.subsystem;
+            var subsystem = m_Session ? m_Session.subsystem : null;
             if (subsystem != null)
             {
                 var configs = subsystem.GetConfigurationDescriptors(Allocator.Temp);

Assets/Scripts/HDRLightEstimation.cs

                     arrow.rotation = Quaternion.LookRotation(mainLightDirection.Value);
                 }
             }
-            else
+            else if (arrow)
             {
                 arrow?.gameObject.SetActive(false);
                 mainLightDirection = null;