Correct Font Awesome tel: link icon

Closes #3489926

js/extlink.js

@@ -503,7 +503,7 @@
    *   HTML string of the Font AweSome telephone icon.
    */
   Drupal.theme.extlink_fa_tel = function (drupalSettings, iconPlacement) {
-    return `<span class="${drupalSettings.data.extlink.extFaLinkClasses}" data-extlink-placement="${iconPlacement}"></span>`;
+    return `<span class="${drupalSettings.data.extlink.extFaTelClasses}" data-extlink-placement="${iconPlacement}"></span>`;
   };
 
   /**