fix: stopping exception when creating new SO

need to call ExitGUI after creating SO or unity will throw exception.

Assets/Mirage/Editor/NetworkPrefabsPropertyDrawer.cs

@@ -58,6 +58,7 @@ private void createNewValue(SerializedProperty property)
 
             property.objectReferenceValue = value;
             property.serializedObject.ApplyModifiedProperties();
+            GUIUtility.ExitGUI();
         }
 
         private void valueGUI(Rect rect, SerializedProperty property, GUIContent label)