fix 'submission not in any period' bug
fix 'submission not in any period' bug

previously, in some courses across different institutions,
when viewing an assignment in an active grading period,
entering a grade via the gradebook caused the cell to gray
out and indicated "This submission is not in any grading
period". this fixes that.

closes CNVS-33802

test plan:
1) in a course with Multiple Grading Periods enabled
   and 51+ students,
2) create an assignment assigned to everyone, and
   make it due within a grading period
3) as a teacher, go to the gradebook and select the
   grading period that the assignment from step 2
   falls in.
4) make sure you can grade every student for the assignment
   and verify you do not see any submission cells gray out
   with the message 'This submission is not in any graidng
   period'

Change-Id: I5f23efdbddc010c44c1f585d66221121308d1942
Reviewed-on: https://gerrit.instructure.com/98292
Reviewed-by: Keith T. Garner <a1a80143a840c140f31c3495ebbd9ec906e09fed@instructure.com>
Tested-by: Keith T. Garner <a1a80143a840c140f31c3495ebbd9ec906e09fed@instructure.com>
QA-Review: KC Naegle <9fbecd016338f9910821a8a5d5d0ae4fc9abfaa5@instructure.com>
Product-Review: Neil Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@instructure.com>

venturehive/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,grahamb/canvas-lms