update lti helper to look for `Student` in context
update lti helper to look for `Student` in context

atomicjolt/OpenAssessments,lumenlearning/OpenAssessments,atomicjolt/OpenAssessments,lumenlearning/OpenAssessments,atomicjolt/OpenAssessments,atomicjolt/OpenAssessments,lumenlearning/OpenAssessments,lumenlearning/OpenAssessments