Only reference InputSystem.Editor on the Editor

Author: jfreire-unity

Packages/com.unity.inputsystem/InputSystem/Plugins/PlayerInput/PlayerInput.cs

@@ -1,11 +1,14 @@
 using System;
 using System.Collections.Generic;
 using UnityEngine.Events;
-using UnityEngine.InputSystem.Editor;
 using UnityEngine.InputSystem.LowLevel;
 using UnityEngine.InputSystem.Users;
 using UnityEngine.InputSystem.Utilities;
 
+#if UNITY_EDITOR
+using UnityEngine.InputSystem.Editor;
+#endif
+
 #if PACKAGE_DOCS_GENERATION || UNITY_INPUT_SYSTEM_ENABLE_UI
 using UnityEngine.InputSystem.UI;
 #endif