Fixed form validation JS. (#8036)

html/js/librenms.js

@@ -87,8 +87,7 @@ $(document).ready(function() {
         var $this = $(this);
         var config_id = $this.data("config_id");
         var config_value = $this.val();
-        var required = $this.prop('required');
-        if (required == false) {
+        if ($this[0].checkValidity()) {
             $.ajax({
                 type: 'POST',
                 url: 'ajax_form.php',