[symfony] Skip data holders with public properties in "NoNullableServiceInConstructorRule"

[bmdevel]

NoNullableServiceInConstructorRule skips data holders only by namespace (\Entity\, \DTO\, \Dto\, \ValueObject\, …). Value objects in other namespaces are reported, for example a domain model that holds optional data:

namespace App\Domain\Model\Offers;

final readonly class Price
{
    public function __construct(
        public Money $total,
        public ?Money $calculated, // reported
    ) {
    }
}

A service does not expose its dependencies as public properties. So a class with public instance properties holds data, and its nullable constructor parameters are optional values. This PR skips such classes. Own, promoted and inherited public properties count, so a child class that passes values to a data-holder parent is skipped too. Static properties do not count.

The existing ReportNullableService fixture (private promoted services) is still reported. 2 new fixtures cover a promoted public property and a child of a public-property parent; both were reported before the change. The full suite, ECS, PHPStan and Rector pass.

[TomasVotruba]

LGTM