ENGCOM-8285: Add collapsible nav in customer account theme blank #28177

 - Merge Pull Request #28177 from mrtuvn/magento2:add-collapsible-nav-in-customer-account
 - Merged commits:
   1. b351d50
   2. 2b9b090

Author: magento-engcom-team

app/design/frontend/Magento/luma/Magento_Customer/layout/customer_account.xml renamed to app/design/frontend/Magento/blank/Magento_Customer/layout/customer_account.xml

@@ -3,6 +3,8 @@
 //  * See COPYING.txt for license details.
 //  */
 
+@import 'module/_collapsible_navigation.less';
+
 //
 //  Theme variables
 //  _____________________________________________