ENGCOM-1870: [BackPort] Resolve Knockout non-unique elements id in console error #15834

Author: VladimirZaets

app/code/Magento/Checkout/view/frontend/web/template/billing-address/form.html

@@ -9,7 +9,7 @@
     <!-- ko template: getTemplate() --><!-- /ko -->
     <!--/ko-->
     <form data-hasrequired="* Required Fields">
-        <fieldset id="billing-new-address-form" class="fieldset address">
+        <fieldset data-bind="attr: { id:'billing-new-address-form-'+index, value:index}" class="fieldset address">
             <!-- ko foreach: getRegion('additional-fieldsets') -->
             <!-- ko template: getTemplate() --><!-- /ko -->
             <!--/ko-->