Remove deprecated code

drupal-check:

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  Line   tests/src/Kernel/ModeratedContentSchedulingTest.php
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  33     Call to deprecated method getLatestRevision() of class Drupal\content_moderation\ModerationInformationInterface:
         in drupal:8.8.0 and is removed from drupal:9.0.0. Use
         RevisionableStorageInterface::getLatestRevisionId and
         RevisionableStorageInterface::loadRevision instead.
  48     Call to deprecated method getLatestRevision() of class Drupal\content_moderation\ModerationInformationInterface:
         in drupal:8.8.0 and is removed from drupal:9.0.0. Use
         RevisionableStorageInterface::getLatestRevisionId and
         RevisionableStorageInterface::loadRevision instead.
  54     Call to deprecated method getLatestRevision() of class Drupal\content_moderation\ModerationInformationInterface:
         in drupal:8.8.0 and is removed from drupal:9.0.0. Use
         RevisionableStorageInterface::getLatestRevisionId and
         RevisionableStorageInterface::loadRevision instead.
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 [ERROR] Found 3 errors