UserCreatedEvent emitted twice when creating user via user management webui #23797

When creating a user account via the user management web ui, the '\OCP\User\Events\UserCreatedEvent' is emitted twice.

Steps to reproduce

1. Create a listener for the '\OCP\User\Events\UserCreatedEvent' event and let it log or do something
2. Create a user via the user management webui
3. See the handle function of the listener is called twice

Expected behaviour

'\OCP\User\Events\UserCreatedEvent' should be emitted once only.

Actual behaviour

'\OCP\User\Events\UserCreatedEvent' is emitted twice.

Server configuration

Tested in official docker based Nextcloud 19.0.4 and 20.0.1

I think this causes the behaviour:

• Emit Hook and Event in UserManager:
  

  server/lib/private/User/Manager.php

  Lines 375 to 378 in f94af85

  	if ($user instanceof IUser) {
  	$this->emit('\OC\User', 'postCreateUser', [$user, $password]);
  	$this->eventDispatcher->dispatchTyped(new UserCreatedEvent($user, $password));
  	}

• React on Hook and emit Event a second time:
  

  server/lib/private/Server.php

  Lines 539 to 546 in f94af85

  	$userSession->listen('\OC\User', 'postCreateUser', function ($user, $password) {
  	/** @var \OC\User\User $user */
  	\OC_Hook::emit('OC_User', 'post_createUser', ['uid' => $user->getUID(), 'password' => $password]);
  	/** @var IEventDispatcher $dispatcher */
  	$dispatcher = $this->get(IEventDispatcher::class);
  	$dispatcher->dispatchTyped(new UserCreatedEvent($user, $password));
  	});

If commenting L544-L545of Server.php the listener is only triggerd once.