Layout builder block cloned wrong revision.

The problem can be reproduced if the page to be translated has blocks which are not pointing to its latest revision.

I tested the patch, it fixed the problem, and the code makes sense to me. I have been thinking on writing a test against it. But, I haven't found a way to update an inline block outside the layout builder to create a new revision which is not referenced by the layout overrides. Maybe, there is another easy way to reproduce the problem on a fresh install?

I added one more line null safety check to handle the case that a revisioned reference in a block could be missing (possibily deleted)

              /** @var \Drupal\Core\Entity\EntityInterface $reference */
              /** @var \Drupal\Core\Entity\EntityInterface $reference_clone */
              $reference = \Drupal::service('entity_type.manager')->getStorage($target_type)->loadRevision($value['target_revision_id']);
              if ($reference) {
                $reference_clone = $reference->createDuplicate();
                $reference_clone->save();
                $new_values[] = [
                  'target_id' => $reference_clone->id(),
                  'target_revision_id' => $reference_clone->getRevisionId(),
                ];
              }