resolve non-unique elements id in console error

Author: neeta-wagento

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

@@ -9,7 +9,7 @@
     <!-- ko template: getTemplate() --><!-- /ko -->
     <!--/ko-->
     <form data-bind="attr: {'data-hasrequired': $t('* 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-->
@@ -21,6 +21,6 @@
                 </label>
             </div>
             <!-- /ko -->
-        </fieldset>
+        </fieldset >
     </form>
 </div>