PHP 8.4 compatibility

Problem/Motivation

When on PHP 8.4, I get many 'Deprecated function' warnings, and some of them are given below:

1. Deprecated function: Drupal\features\FeaturesManager::isFeatureModule(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

2. Deprecated function: Drupal\features\FeaturesManager::listPackageDirectories(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

3. Deprecated function: Drupal\features\FeaturesManager::getFeaturesModules(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

4. Deprecated function: Drupal\features\FeaturesManager::initPackage(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

5. Deprecated function: Drupal\features\FeaturesManager::assignConfigDependents(): Implicitly marking parameter $item_names as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

6. Deprecated function: Drupal\features\FeaturesManager::assignPackageDependencies(): Implicitly marking parameter $package as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

7. Deprecated function: Drupal\features\FeaturesManager::getPackageObject(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

8. Deprecated function: Drupal\features\FeaturesManager::listExistingConfig(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

9. Deprecated function: Drupal\features\FeaturesManager::getExportInfo(): Implicitly marking parameter $bundle as nullable is deprecated, the explicit nullable type must be used instead in include() (line 582 of C:\Users\mypc\www\my_site\drupal\vendor\composer\ClassLoader.php).

Proposed resolution

Use nullable types.