Fix test fails on Drupal 10.1.x

Tests are currently failing against Drupal 10.1.x due to #3225395: Repeated entity type labels in entity_test module, which changed the label for the EntityTestMulRevChanged entity type, which we are fond of using in our tests.

To fix this, we probably just need to retrieve the entity type label dynamically and use that in the check instead of hardcoding the label in \Drupal\Tests\search_api\Functional\ViewsTest::testViewsAdmin(). We can go back to hardcoding it once we depend on Drupal 10.1.0.