PHP8.4 deprecations: implicitly nullable parameter

[sneakyvv]

Running tests gives a bunch of deprecations; for example:

Deprecated: Klaviyo\Integration\Model\UseCase\ScheduleBackgroundJob::scheduleSubscriberSyncJob(): Implicitly marking parameter $name as nullable is deprecated, the explicit nullable type must be used instead in. ../vendor/klaviyo/shopware-klaviyo/src/Model/UseCase/ScheduleBackgroundJob.php on line 136

public function scheduleSubscriberSyncJob(
        array $subscriberIds,
        string $parentJobId,
        Context $context,
        string $name = null
    ): void {

should become

public function scheduleSubscriberSyncJob(
        array $subscriberIds,
        string $parentJobId,
        Context $context,
        ?string $name = null
    ): void {

See https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated