Check session variable before delivering cached page

@flynorc‍

Register should work via shopware like now, but after sign up - you shouldn’t sign in customer automatically.

Instead of this you should bind erp account with shopware account via  some uniq identifier and don’t use shopware auth. Instead of shopware sign in page - you should show your custom sign in page, after validate data with your 3rd part service - you fetch shopware user based on uniq identifier which bind service and shopware profile and do shopware login. In such behaviour customer don’t need to do two separate login and you can be sure each signed in customer valid with 3rd part service.