preload submission attempt assignment
preload submission attempt assignment

refs CNVS-31321

it's used by Submission#user_can_read_grade?, which is called by
filter_attributes_for_user, which is triggered by json serialization

Change-Id: I0daba4eaeb874cc39767019ccc79e211c89ac674
Reviewed-on: https://gerrit.instructure.com/88821
Tested-by: Jenkins
Reviewed-by: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>
Product-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
QA-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>

matematikk-mooc/canvas-lms,dgynn/canvas-lms,dgynn/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,venturehive/canvas-lms,SwinburneOnline/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms