DefaultSingleLazyPluginCollection::setConfiguration() accepts NULL but ConfigurableInterface::setConfiguration() does not

Problem/Motivation

Ran into this while working on #3364109: Configuration schema & required values: add test coverage for `nullable: true` validation support.

signature \Drupal\Component\Plugin\ConfigurableInterface::setConfiguration(array $configuration) (note type hint)
🆚
signature \Drupal\Component\Plugin\LazyPluginCollection::setConfiguration($configuration) (note NO type hint)
🆚
\Drupal\Core\Plugin\DefaultSingleLazyPluginCollection::setConfiguration() implementation of LazyPluginCollection::setConfiguration():

  public function setConfiguration($configuration) {
    $this->configuration = $configuration;
    $plugin = $this->get($this->instanceId);
    if ($plugin instanceof ConfigurableInterface) {
      $plugin->setConfiguration($configuration);
    }
    return $this;
  }

Steps to reproduce

$block = Block::load('block.block.olivero_content');
$block->set('settings', NULL);
$typed_data = $this->container->get('typed_data_manager');
$definition = $typed_data->createDataDefinition('entity:block');
$violations = $typed_data->create($definition, $block)->validate();

Results in:

TypeError: Drupal\Core\Block\BlockBase::setConfiguration(): Argument #1 ($configuration) must be of type array, null given, called in /Users/wim.leers/core/core/lib/Drupal/Core/Plugin/DefaultSingleLazyPluginCollection.php on line 85

/Users/wim.leers/core/core/lib/Drupal/Core/Block/BlockPluginTrait.php:79
/Users/wim.leers/core/core/lib/Drupal/Core/Plugin/DefaultSingleLazyPluginCollection.php:85
/Users/wim.leers/core/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php:165
…

Same problem in \Drupal\Core\Plugin\DefaultLazyPluginCollection::setConfiguration() (try visibility on

Proposed resolution

Make
\Drupal\Core\Plugin\DefaultSingleLazyPluginCollection::setConfiguration()
\Drupal\Core\Plugin\DefaultLazyPluginCollection::setConfiguration()
narrow the data it receives

Remaining tasks

None.

User interface changes

None.

API changes

None.

Data model changes

None.

Release notes snippet

N/A