fix: Server only session issues with parent synchronize and networkobjecteditor (#3139)

* fix

Fixed issue where NetworkObjectEditor would throw an exception when you tried to view the NetworkObject.Observers in the inspector view when in playmode.

* fix

Fixed issue where the parent sync message was ignoring deserialization on the server side (clients can parent if the NetworkObject has the allow clients to parent flag set).

Author: NoelStephensUnity

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

@@ -88,6 +88,14 @@ public override void OnInspectorGUI()
 
                         while (observerClientIds.MoveNext())
                         {
+                            if (!m_NetworkObject.NetworkManager.ConnectedClients.ContainsKey(observerClientIds.Current))
+                            {
+                                if ((observerClientIds.Current == 0 && m_NetworkObject.NetworkManager.IsHost) || observerClientIds.Current > 0)
+                                {
+                                    Debug.LogWarning($"Client-{observerClientIds.Current} is listed as an observer but is not connected!");
+                                }
+                                continue;
+                            }
                             if (m_NetworkObject.NetworkManager.ConnectedClients[observerClientIds.Current].PlayerObject != null)
                             {
                                 EditorGUILayout.ObjectField($"ClientId: {observerClientIds.Current}", m_NetworkObject.NetworkManager.ConnectedClients[observerClientIds.Current].PlayerObject, typeof(GameObject), false);

com.unity.netcode.gameobjects/Runtime/Messaging/Messages/ParentSyncMessage.cs

@@ -70,10 +70,6 @@ public void Serialize(FastBufferWriter writer, int targetVersion)
         public bool Deserialize(FastBufferReader reader, ref NetworkContext context, int receivedMessageVersion)
         {
             var networkManager = (NetworkManager)context.SystemOwner;
-            if (!networkManager.IsClient)
-            {
-                return false;
-            }
 
             ByteUnpacker.ReadValueBitPacked(reader, out NetworkObjectId);
             reader.ReadValueSafe(out m_BitField);