adds for active students check on assignments has_submission method to allow assignment types to be deleted when submissions for any assignments only belong to deactive students
adds for active students check on assignments has_submission method to allow assignment types to be deleted when submissions for any assignments only belong to deactive students

UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development