Removing final usage of UnityEditorInternal to fix tests

com.unity.perception/Tests/Runtime/GroundTruthTests/SegmentationGroundTruthTests.cs

 using System.Linq;
 using NUnit.Framework;
 using Unity.Collections;
-using UnityEditorInternal;
 using UnityEngine;
 using UnityEngine.Perception.GroundTruth;
 using UnityEngine.Rendering;