[Assignments] Accurately identify group assignment submissions

[AndrewDOchs]

Problem statement:

When a group assignment is submitted by a single member of a group, "Speedgrader will assign the submission to one of the students in the group as the submitter for the group submission, and there is no guarantee it will be the user for that group that submitted it". This potentially incorrect attribution of which member of a group actually submitted an assignment for their group can be visible to instructors in notifications sent out regarding that submission. This came up in a case where we had a particular group with one student member that was in the process of dropping the course, but the drop had not yet gone through. This student had never accessed the course nor participated in the group at all, but was attributed by Speedgrader as the individual member of the group that had actually submitted the assignment. This caused a great deal of confusion. I can see no advantage at all to Speedgrader randomly assigning a student as a group assignment submitter if that's not always going to be the actual submitting student.

Proposed solution:

#1 solution: For any group submission, the student who submitted the assignment for their group should be the only student attributed as submitter for their group anywhere and everywhere an instructor might see that information. There should never be a different member of the group listed as submitting a group assignment NOT actually submitted by them. #2 solution: For any group submission, there should never be an individual student attributed as submitter for their group. It should be listed as a group submission anywhere and everywhere an instructor can see information about that submission.

User role(s):

admin,instructor,ta