[Routing] Do not raise ImplicitToStringCast when EnumRequirement is a…

[sidz]

This PR handles ImplicitToStringCast when EnumRequirement is used in the Route requirements.

New feature introduced in Symfony Routing 6.1: https://symfony.com/blog/new-in-symfony-6-1-improved-routing-requirements-and-utf-8-parameters#using-php-backedenum-as-route-requirements

Current code does not pass test on PHP 8.1. Need to improve pipeline.

I'm not sure how to solve this kind of issue. I suppose smth wrong on Psalm end

1) Route: ImplicitToStringCast error is not raised when array of EnumRequirement is assigned
 Test  tests/acceptance/acceptance/Route.feature:ImplicitToStringCast error is not raised when array of EnumRequirement is assigned
 Step  Can see no errors 
 Fail  There were errors: 
| ParseError | Promoted property name clashes with an existing property         |
| ParseError | Promoted property requirements clashes with an existing property |
| ParseError | Promoted property options clashes with an existing property      |
| ParseError | Promoted property defaults clashes with an existing property     |
| ParseError | Promoted property host clashes with an existing property         |
| ParseError | Promoted property condition clashes with an existing property    |
| ParseError | Promoted property priority clashes with an existing property     |
| ParseError | Promoted property env clashes with an existing property          |