Update the testproject asmdef so the sceneEventDataTests compile

Author: EmandM

testproject/Assets/Tests/Runtime/TestProject.Runtime.Tests.asmdef

@@ -38,6 +38,11 @@
             "name": "com.unity.addressables",
             "expression": "",
             "define": "TESTPROJECT_USE_ADDRESSABLES"
+        },
+        {
+          "name": "Unity",
+          "expression": "6000.4.0a3",
+          "define": "SCENE_MANAGEMENT_SCENE_HANDLE_NO_INT_CONVERSION"
         }
     ],
     "noEngineReferences": false