Fix stripe load on d8 webforms

js/crm.payment.js

@@ -112,7 +112,7 @@
       var submit = null;
       if (CRM.payment.getIsDrupalWebform()) {
         submit = this.form.querySelectorAll('[type="submit"].webform-submit');
-        if (!submit) {
+        if (submit.length === 0) {
           // drupal 8 webform
           submit = this.form.querySelectorAll('[type="submit"].webform-button--submit');
         }