Please update for Symfony > 7.1

[Evgeny1973]

The "Symfony\Component\HttpKernel\DependencyInjection\Extension" class is considered internal since Symfony 7.1, to be deprecated in 8.1; use Symfony\Component\DependencyInjection\Extension\Extension instead. It may change without further notice. You should not use it from "Exercise\HTMLPurifierBundle\DependencyInjection\ExerciseHTMLPurifierExtension".