Stop submissions from circularly updating assignments
Stop submissions from circularly updating assignments

Fixes: CNVS-38667

When Assignment#update_submissions is being called it's triggering
Submission#update_assignment to be called without indicating that we
don't need to update the assignment again, this patch fixes that so the
assignment update won't be circular.

Test Plan:
- Stuff still works

Change-Id: I7deb87081725396fa3cfebda25605238b9614a57
Reviewed-on: https://gerrit.instructure.com/122624
Reviewed-by: Neil Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@instructure.com>
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Tested-by: Jenkins
Reviewed-by: Michael Brewer-Davis <785693f4c81267e5b88c0f98d39b56a39a2b6910@instructure.com>
QA-Review: Jeremy Putnam <b030d6d6f199f844ec424882be473c2ab9adc93b@instructure.com>
Product-Review: Tyler Pickett <3f20fcf21b1970c94966160adcf831eedd808a06@instructure.com>

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