Fix compile error when WAVEXR_ESSENCE_RENDERMODEL is installed

Author: lawwong

Assets/HTC.UnityPlugin/VRModule/Modules/UnityXRModule.cs

@@ -55,6 +55,9 @@ public override void CreateCamera(VRCameraHook hook)
         [RenderModelHook.CreatorPriorityAttirbute(0)]
         private class RenderModelCreator : RenderModelHook.DefaultRenderModelCreator
         {
+#if VIU_WAVEXR_ESSENCE_RENDERMODEL
+            private uint m_index = INVALID_DEVICE_INDEX;
+#endif
             public override bool shouldActive { get { return s_moduleInstance == null ? false : s_moduleInstance.isActivated; } }
 
             public override void UpdateRenderModel()
@@ -937,9 +940,9 @@ private Quaternion GetDeviceFeatureValueOrDefault(InputDevice device, InputFeatu
             return default;
         }
 
-        private Hand GetDeviceFeatureValueOrDefault(InputDevice device, InputFeatureUsage<Hand> feature)
+        private UnityEngine.XR.Hand GetDeviceFeatureValueOrDefault(InputDevice device, InputFeatureUsage<UnityEngine.XR.Hand> feature)
         {
-            Hand value;
+            UnityEngine.XR.Hand value;
             if (device.TryGetFeatureValue(feature, out value))
             {
                 return value;
@@ -1026,5 +1029,5 @@ private static string CharacteristicsToString(InputDeviceCharacteristics ch)
             return str;
         }
 #endif
-    }
-}
+        }
+    }