PHP 8.4 support

[andypost]

I started testing Drupal 11 with PHP 8.4 and faced issues because of https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated

I did patch some code (will provide PR) but still getting deprecation warnings from mocks

Probably the \Prophecy\Doubler\ClassPatch\DisableConstructorPatch::apply() needs changes

    OK (6 tests, 154 assertions)
    
    Other deprecation notices (2)
    
      1x:
    Double\Drupal\Core\Cache\Context\CacheContextsManager\P1::__construct():
    Implicitly marking parameter $container as nullable is deprecated, the
    explicit nullable type must be used instead
        1x in VariationCacheTest::setUp from Drupal\Tests\Core\Cache
    
      1x:
    Double\Drupal\Core\Cache\Context\CacheContextsManager\P1::__construct():
    Implicitly marking parameter $contexts as nullable is deprecated, the
    explicit nullable type must be used instead
        1x in VariationCacheTest::setUp from Drupal\Tests\Core\Cache