FIX: disallow connected user to display add and login forms

a connected user is redirected to his profile page
when he tries to view the following pages:
- /<lang>/users/add
- /<lang>/users/login
4 jobs for develop in 5 minutes and 20 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #50278
composer_validate

00:01:10

passed #50279
php-lint

00:01:19

passed #50280
phpcs

00:00:48

passed #50281
phpunit

00:05:19

56.64%