[2.0.0-beta2] Check PropTypeInterface::normalize()

Add proper reference to the UI Patterns Settings isue.

Drupal\Core\Render\Component\Exception\InvalidComponentException: [attributes] String value found, but an object is required was also found while working on 📌 [2.0.0-beta2] ComponentElementAlter: normalize attributes Active

Unfortunately, only by the gitlab pipeline, while running phpunit. I am still not able to reproduce it locally, even running the same test.

will be covered by 📌 [2.0.0-beta2] ComponentElementAlter: normalize attributes Active