[PHP8.4] Misc NULL deprecation warning on a few files

Problem/Motivation

After testing my D11 instance on PHP 8.4, I've come across a few issues:

Deprecated: Drupal\page_manager\Entity\PageVariantViewBuilder::resetCache(): Implicitly marking parameter $entities as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/html/modules/contrib/page_manager/src/Entity/PageVariantViewBuilder.php on line 46

Deprecated: Drupal\page_manager_ui\Form\VariantPluginAddBlockForm::buildForm(): Implicitly marking parameter $request as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/html/modules/contrib/page_manager/page_manager_ui/src/Form/VariantPluginAddBlockForm.php on line 65

Deprecated: Drupal\page_manager\Plugin\SectionStorage\PageManagerSectionStorage::access(): Implicitly marking parameter $account as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/html/modules/contrib/page_manager/src/Plugin/SectionStorage/PageManagerSectionStorage.php on line 206

PHP Deprecated:  Drupal\entityqueue\Controller\EntityQueueUIController::subqueueListForEntity(): Implicitly marking parameter $entity as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/html/modules/contrib/entityqueue/src/Controller/EntityQueueUIController.php on line 76

Steps to reproduce

If you have the module installed, by running drush you'll get the errors

Proposed resolution

Explicitelly declare the variable as nullable: https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullabl...

Remaining tasks

N/A

User interface changes

N/A

API changes

N/A

Data model changes

N/A