remove scenemanagement namespace

Project/Assets/ML-Agents/Examples/Dodgeball/Scripts/PlayBackgroundAudio.cs

 using System.Collections;
 using System.Collections.Generic;
-using UnityEditor.SceneManagement;
 using UnityEngine;
 
 

Project/ProjectSettings/BurstAotSettings_StandaloneLinux64.json

+{
+  "MonoBehaviour": {
+    "Version": 3,
+    "EnableBurstCompilation": true,
+    "EnableOptimisations": true,
+    "EnableSafetyChecks": false,
+    "EnableDebugInAllBuilds": false,
+    "UsePlatformSDKLinker": false,
+    "CpuMinTargetX32": 0,
+    "CpuMaxTargetX32": 0,
+    "CpuMinTargetX64": 0,
+    "CpuMaxTargetX64": 0,
+    "CpuTargetsX64": 72
+  }
+}