chore: fix CI

[vincentchalamon]

Note: Symfony dev CI jobs are failing because of symfony/symfony#50864

Fix CS

src/GraphQl/Resolver/Factory/ResolverFactory.php resolve private method has been updated to allow null default value (required as required arguments cannot be declared after optional ones).

Fix nullable_type_declaration_for_default_null_value CS rule (nullable_type_declaration_for_default_null_value.use_nullable_type_declaration is now enabled by default in PHP CS Fixer - cf. PHP-CS-Fixer/PHP-CS-Fixer#7773)

Fix PHPUnit Doctrine jobs

Fix self deprecation (missing configuration in component tests).

Since api-platform/core 3.2: Using doctrine/inflector is deprecated since API Platform 3.2 and will be removed in API Platform 4. Use symfony/string instead. Run "composer require symfony/string" and set "keep_legacy_inflector" to false in config.

Fix Doctrine ORM enable_lazy_ghost_objects deprecation in tests configuration

Doctrine ORM enable_lazy_ghost_objects must be set to true in configuration (cf. doctrine/DoctrineBundle#1733).

Since doctrine/doctrine-bundle 2.11: Not setting "enable_lazy_ghost_objects" to true is deprecated.