Registration creation service leaks data

Added a failing test that showcases the problem:

https://git.drupalcode.org/issue/recurring_events-3452632/-/jobs/1783093

There was 1 failure:
1) Drupal\Tests\recurring_events_registration\Kernel\RegistrationCreationServiceTest::testServiceInstantiation
A newly instantiated service should not have an event series.
Failed asserting that an object is empty.

Defining the service as non-shared solves the problem. The test passes now: https://git.drupalcode.org/issue/recurring_events-3452632/-/jobs/1783235

The other test failures are not related to this issue, ref. 🐛 Failing tests on main branch Active

Thanks for this I'll get this merged.

This has been merged.

Automatically closed - issue fixed for 2 weeks with no activity.