Add a null check

Author: sinai-dev

src/Config/ConfigManager.cs

@@ -55,7 +55,7 @@ public static void Init(ConfigHandler configHandler)
             InternalHandler.LoadConfig();
 
 #if STANDALONE
-            Loader.Standalone.ExplorerEditorBehaviour.Instance.LoadConfigs();
+            Loader.Standalone.ExplorerEditorBehaviour.Instance?.LoadConfigs();
 #endif
 
             //InitConsoleCallback();