Add `EnumTypeCaster` to hydrator configuration

It seems to me that this order will be good:

FormHydrator::class => [
        '__construct()' => [
            'hydrator' => DynamicReference::to([
                'class' => Hydrator::class,
                '__construct()' => [
                    'typeCaster' => new CompositeTypeCaster(
                        new NullTypeCaster(emptyString: true),
                        new PhpNativeTypeCaster(),
                        new NonArrayTypeCaster(),
                        new \Yiisoft\Hydrator\TypeCaster\EnumTypeCaster(),
                        new HydratorTypeCaster(),
                    ),
                ],
            ]),
        ],
    ],

Locate the FormHydrator configuration and the Hydrator construction described in the issue. Compare the type-caster order with the proposed EnumTypeCaster entry, then verify that enum-valued form fields are handled by the configured hydrator.