fix issue with multiple GTM IDs

this do not take on consideration the use of multiple ids

view/frontend/templates/script.phtml

@@ -32,7 +32,7 @@ $events = ($config->waitForUserInteraction() === false)
                 j.async = true;
                 j.src = '<?= $config->getGoogleTagmanagerUrl() ?>' + '/gtm.js?id=' + i + dl;
                 f.parentNode.insertBefore(j, f);
-            })(window, document, 'script', 'dataLayer', '<?= $config->getId() ?>');
+            })(window, document, 'script', 'dataLayer', '<?= $gtmId ?>');
             <?php endforeach; ?>
         }