[ISSUE-11140][BUGFIX] Skip store code admin from being detected in ca…

[sylvainraye]

…se of store code in url configured

Show a 404 error page if /admin is called but it was customized and the store code url is enabled

Description

When store code url is configured for frontend, the url admin is also involved to set the pathinfo but it should be not as it is a different expected area and that admin store code is "hard coded" in DB and PHP Class

Fixed Issues

1. Going to '/admin' while using storecodes in url and a different adminhtml url will throw exception #11140: Going to '/admin' while using storecodes in url and a different adminhtml url will throw exception

Manual testing scenarios

1. Everything is explained into Going to '/admin' while using storecodes in url and a different adminhtml url will throw exception #11140

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)