Grading webhook: remove older grading comments with `keepLastNComments`
Some grades are pushed over the grading webhook repeatedly for individual submissions. Each grade push adds a new comment to a submission. With a new optional propertySubmitted by Elmer van Chastelet on 24 February 2021 at 09:13
"keepLastNComments": "n"the last n grading comments will be kept, older ones will be removed.