Ensure that each billing address form DOM element has a unique id

[dangron]

magento/magento2#15349

[dangron]

$ composer update space48/magento2-patches
Loading composer repositories with package information
Updating dependencies (including require-dev)                                                            
Package operations: 1 install, 0 updates, 0 removals
  - Installing space48/magento2-patches (dev-patch-magento2-issue-15349 ba135a4): Cloning ba135a46a8 from cache
Package sjparkinson/static-review is abandoned, you should avoid using it. Use phpro/grumphp instead.
Writing lock file
Generating autoload files
Processing patches configuration
  - Applying patches for magento/module-checkout (1)
    ~ space48/magento2-patches: patches/Magento_Checkout/billing-address-form.patch [NEW]
      Ensure that each billing address form DOM element has a unique id https://github.com/magento/magento2/pull/15349

  - Applying patches for magento/module-configurable-product (1)
    ~ space48/magento2-patches: patches/Magento_ConfigurableProduct/magento2-issue-11953.patch [NEW]
      Add frontend validation for SKU on configurable product variation generation in admin panel

  - Applying patches for magento/module-swatches (1)
    ~ space48/magento2-patches: patches/Magento_Swatches/12036.patch [NEW]
      prevent attribute beforesave plugin from nulling attribute options

Writing patch info to install file

$ git diff vendor/magento/module-checkout/view/frontend/web/template/billing-address/form.html
diff --git a/vendor/magento/module-checkout/view/frontend/web/template/billing-address/form.html b/vendor/magento/module-checkout/view/frontend/web/template/billing-address/form.html
index 1be754934..1568045d4 100644
--- a/vendor/magento/module-checkout/view/frontend/web/template/billing-address/form.html
+++ b/vendor/magento/module-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-->