PSPAYPAL-915 Credit card validation

Call `dispatchEvent(new CustomEvent('submit', {cancelable: true}));`
instead of `sudmit` method in order to trigger submit event and hence
form validation.

Author: mparienti

views/smarty/frontend/blocks/page/checkout/checkout_order_btn_submit_bottom.tpl

@@ -8,7 +8,7 @@
     submitButton.addEventListener('click', function() {
     event.preventDefault();
     this.disabled = true;
-    orderConfirmAgbBottom.submit();
+    orderConfirmAgbBottom.dispatchEvent(new CustomEvent('submit', {cancelable: true}));
     });
     [{/capture}]
     [{oxscript add=$smarty.capture.oscpaypal_madClickPrevention}]

views/twig/extensions/themes/default/page/checkout/order.html.twig

@@ -81,7 +81,7 @@
             submitButton.addEventListener('click', function(event) {
             event.preventDefault();
             this.disabled = true;
-            orderConfirmAgbBottom.submit();
+            orderConfirmAgbBottom.dispatchEvent(new CustomEvent('submit', {cancelable: true}));
             });
         {% endcapture %}
         {{ script({ add: oscpaypal_madClickPrevention, dynamic: __oxid_include_dynamic }) }}