Auto-archive after submitting & no longer pre-marking answer choice as correct

A couple of minor improvements:

1. We decided to auto-archive your notifications after you submit your assessment of a free response in order to make that whole process more convenient.

2. We also stopped marking the first multiple choice as "correct" by default. We heard that this was causing some inadvertent mistakes where the wrong answer choice got marked correct, so we hope this prevents that moving forward!