setPublished/setUnpublished called without verifying EntityPublishedInterface

Problem/Motivation

While working on #3355087: Support for non-bundle entity types I used an entity type that does not implement EntityPublishedInterface and caused a crash at scheduler.module:828/836

Drupal\Tests\scheduler\Functional\SchedulerDeleteEntityTest::testDeleteEntityWithPastDates with data set "#entity_test_no_bundle"
Error: Call to undefined method Drupal\entity_test\Entity\EntityTestNoBundle::setUnpublished()

/builds/issue/scheduler-3355087/scheduler.module:836

Steps to reproduce

Proposed resolution

  if ($entity instanceof EntityPublishedInterface) {
    $entity->setPublished(); // or setUnpublished()
  }

Or validate scheduler plugins are targeting entity types which implement EntityPublishedInterface

Remaining tasks

User interface changes

API changes

Data model changes