MAGETWO-45060: Inconsistent credit card validation behavior

- Fixed displaying input forms of credit card

Author: Dell-

app/code/Magento/Braintree/view/frontend/web/js/view/payment/method-renderer/cc-form.js

@@ -141,7 +141,7 @@ define(
                 this.isCcFormShown = ko.computed(function () {
 
                     return !this.useVault() ||
-                        this.selectedCardToken() === 'undefined' ||
+                        this.selectedCardToken() === undefined ||
                         this.selectedCardToken() === '';
                 }, this);