UI 자동화를 위해 바인딩 기능 구현

- 유니티 에셋 인증 오류로 meta 재생성

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/ReactiveProperty.cs

@@ -0,0 +1,28 @@
+#if UNITY_EDITOR
+using System;
+
+namespace UnityEngine.InputSystem.Editor
+{
+    internal class ReactiveProperty<T>
+    {
+        private T m_Value;
+        public event Action<T> Changed;
+
+        public T value
+        {
+            get => m_Value;
+            set
+            {
+                m_Value = value;
+                Changed?.Invoke(m_Value);
+            }
+        }
+
+        public void SetValueWithoutChangeNotification(T value)
+        {
+            m_Value = value;
+        }
+    }
+}
+
+#endif