Validate that repository object version for user version has cocina

[justinlittman]

For this ticket, add an additional validator to UserVersion to ensure that its RepositoryObjectVersion has cocina. (Recall that legacy RepositoryObjectVersions don't have cocina.)

The easiest way to check if a RepositoryObjectVersion has cocina is to check if cocina_version is present (though it might be nice to add a helper method for this).