[Web] Clean PHP code by removing unused variables (#3646)

* [WEB] $lang is not used in this context

* [Web] $stmt variable is not used

data/web/inc/functions.presets.inc.php

@@ -1,6 +1,5 @@
 <?php
 function presets($_action, $_kind) {
-  global $lang;
   switch ($_action) {
     case 'get':
       if ($_SESSION['mailcow_cc_role'] != "admin" && $_SESSION['mailcow_cc_role'] != "domainadmin") {