fix: Stop checking hierarchy changed in playmode (#3026)

* fix

stop checking for hierarchy changes when we enter into play mode.

* update

adding changelog entry

* style

fixing spelling mistake.

* update

adding PR number to changelog entry.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -12,6 +12,8 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 ### Fixed
 
+- Fixed issue where the `NetworkManagerHelper` was continuing to check for hierarchy changes when in play mode. (#3026)
+
 ### Changed
 
 ## [2.0.0-pre.4] - 2024-08-21

com.unity.netcode.gameobjects/Editor/NetworkManagerHelper.cs

@@ -61,6 +61,12 @@ private static void EditorApplication_playModeStateChanged(PlayModeStateChange p
                     {
                         s_LastKnownNetworkManagerParents.Clear();
                         ScenesInBuildActiveSceneCheck();
+                        EditorApplication.hierarchyChanged -= EditorApplication_hierarchyChanged;
+                        break;
+                    }
+                case PlayModeStateChange.EnteredEditMode:
+                    {
+                        EditorApplication.hierarchyChanged += EditorApplication_hierarchyChanged;
                         break;
                     }
             }
@@ -110,6 +116,12 @@ private static void ScenesInBuildActiveSceneCheck()
         /// </summary>
         private static void EditorApplication_hierarchyChanged()
         {
+            if (Application.isPlaying)
+            {
+                EditorApplication.hierarchyChanged -= EditorApplication_hierarchyChanged;
+                return;
+            }
+
             var allNetworkManagers = Resources.FindObjectsOfTypeAll<NetworkManager>();
             foreach (var networkManager in allNetworkManagers)
             {