correctly grab externalUserId on grade create
correctly grab externalUserId on grade create

Also verify the api token on grade endpoint if there is one.
There can be anonymous users, so don't need to do it always

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