ENGCOM-5535: Resolve Field 'Billing ZIP Code' shows and disappears immediately in 'Orders and Returns' form #23747

 - Merge Pull Request #23747 from edenduong/magento2:2.3-bugfix/order_return_field_issue23746
 - Merged commits:
   1. a7f696f

Author: magento-engcom-team

app/code/Magento/Sales/view/frontend/templates/guest/form.phtml

@@ -48,7 +48,7 @@
                        data-validate="{required:true, 'validate-email':true}"/>
             </div>
         </div>
-        <div id="oar-zip" class="field zip required">
+        <div id="oar-zip" style="display: none;" class="field zip required">
             <label class="label" for="oar_zip"><span><?= $block->escapeHtml(__('Billing ZIP Code')) ?></span></label>
 
             <div class="control">