Importing Examples Hub scene with UPM generates SU namespace error

[elbuhofantasma]

Describe the bug

When importing the MRTK Examples Hub scene with UPM into a project, the following warnings below are generated.

To reproduce

Steps to reproduce the behavior:

1. Create a new project in Unity 2020
2. Import the MRTK UPM packages to the project via the Package Manager
3. Under the Examples package, import the 'Experimental - Examples Hub' sample
4. See error

Expected behavior

Importing example scenes do not generate errors in the Unity console.

Your setup (please complete the following information)

• Unity Version 2020.3.7
• MRTK Version 2.7

Target platform (please complete the following information)

• OpenXR
• UWP

[MaxWang-MS]

We are removing the following script from MRTK for now as it is not used by any scene/other script at the moment. The script is intended to properly clean up the mesh/GameObject generated in the Scene Understanding example scene before switching to another scene. We are planning to readd the script when we place it in a scene at a later date.

using Microsoft.MixedReality.Toolkit;
using Microsoft.MixedReality.Toolkit.Experimental.SceneUnderstanding;
using Microsoft.MixedReality.Toolkit.SceneSystem;
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace Microsoft.MixedReality.Toolkit.Examples.Demos
{
    public class SceneSystemUnloadingCheck : MonoBehaviour
    {
        public DemoSceneUnderstandingController SUController;
        private bool isCleared = false;

        void Start()
        {
            IMixedRealitySceneSystem sceneSystem = MixedRealityToolkit.Instance.GetService<IMixedRealitySceneSystem>();
            sceneSystem.OnWillUnloadContent += HandleSceneOperation;
        }

        private void HandleSceneOperation(IEnumerable<string> obj)
        {
            if (isCleared == false)
            {
                SUController.ClearScene();
                isCleared = true;
            }
        }
    }
}