[Gradebook] Add no submission to the options for Complete/Incomplete in the "display as" for grades on assignments

[lbethany]

Problem statement:

We have some courses that want to be able to assign a "complete" / "incomplete" / "no submission" for assignments, in the "grade display as" feature. Could a "no submission" be added?

Proposed solution:

Add a "no submission" option to the complete / incomplete options in the "grade display as" feature.

User role(s):

instructor,student,ta