Removed duplicated info on Symfony dev mode

Author: glye

docs/infrastructure_and_maintenance/security/security_checklist.md

@@ -168,7 +168,6 @@ Reduce your attack surface by exposing only what you must.
 
 Only expose Symfony production mode openly on the internet.
 Don't expose the dev mode on the internet, otherwise you may disclose things like `phpinfo` and environment variables.
-Exposing the dev mode exposes things like `phpinfo`, environment variables, and more.
 
 For more information about securing Symfony-based systems, see [Authentication and authorisation]([[= symfony_doc =]]/security.html), [more on this subject]([[= symfony_doc =]]/security.html#learn-more), and Symfony's [secrets management system]([[= symfony_doc =]]/configuration/secrets.html).