Script editor help: Prevent loading empty instances from layout

(cherry picked from commit 71f6c96288)

editor/plugins/script_editor_plugin.cpp

@@ -2317,6 +2317,9 @@ void ScriptEditor::set_window_layout(Ref<ConfigFile> p_layout) {
 	for (int i = 0; i < helps.size(); i++) {
 
 		String path = helps[i];
+		if (path == "") { // invalid, skip
+			continue;
+		}
 		_help_class_open(path);
 	}