PHP 8.4 Deprecation: explicit nullable type must be used

Problem/Motivation

Deprecated: Drupal\disqus\DisqusCommentManager::__construct(): Implicitly marking parameter $file_url_generator as nullable is deprecated, the explicit nullable type must be used instead in /app/web/modules/contrib/disqus/src/DisqusCommentManager.php on line 77

is displayed on content types where disqus commenting is disabled.

Reguardless PHP 8.4 best practices dictate we declare this as possibly being nullable. To extend the PHP compatibility for the must versions of PHP, we can use the PHP 7.1 added support for nullable types, which introduced the ?TYPE syntax to declare the types as nullable:

 public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, AccountInterface $current_user, ModuleHandlerInterface $module_handler, ConfigFactory $config_factory, ?FileUrlGeneratorInterface $file_url_generator = NULL) {
}