Replace the entity manager with the entity type manager in the code base.

Failing cause we have no tests written.

13:28:22 ERROR: No valid tests were specified.

Whats this benefit of this change?

There is no property 'entityTypeManager' in the class Drupal\ctools\Plugin\Deriver\EntityDeriverBase

I still get the same error as pointed out by @nicolas85.
Even if Drupa\Core\Entity\EntityTpyeManagerInterface. has been used I don't see it getting injected anywhere.

If we take a look at Drupal\ctools\Plugin\Deriver\EntityDeriverBase
It still utilizes \Drupal\Core\Entity\EntityManagerInterface

 /**
   * The entity manager.
   *
   * @var \Drupal\Core\Entity\EntityManagerInterface
   */
  protected $entityManager;

  /**
   * Constructs new EntityViewDeriver.
   *
   * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
   *   The entity manager.
   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
   *   The string translation service.
   */
  public function __construct(EntityManagerInterface $entity_manager, TranslationInterface $string_translation) {
    $this->entityManager = $entity_manager;
    $this->stringTranslation = $string_translation;
  }

So unless ctools is updated this commit will not work.

Looks like even with most up to date ctools, this still breaks.

Its also now a bug since we introduced a breaking commit.

I have posted a patch in ctools for this https://www.drupal.org/node/2761717
If that doesn't get merged anytime soon, one other way to fix this would be to replace $this->entityTypeManager with \Drupal::entityTypeManager though this is obviously not a good way to fix this.

In all the derivers we just need to change $this->entityTypeManager back to $this->entityManager in all instances. The parent class EntityDeriverBase still uses entityManager as the property name. Once ctools commits the above issue we can switch it.

I think this is a just a task, since everything works still.

This was done as part of the Drupal 9 readiness in #3154535: Drupal 9