CNS-625: Student cannot submit the assignment created by "Grade replies separately" checkbox
CNS-625: Student cannot submit the assignment created by "Grade replies separately" checkbox

This also fix CNS-710: Check problems for discussion topics with graded
replies caused by the upstream merge

HotChalk/canvas-lms,HotChalk/canvas-lms,HotChalk/canvas-lms,HotChalk/canvas-lms