speedgrader: show "graded" checkbox for excused assignments
speedgrader: show "graded" checkbox for excused assignments

fixes CNVS-21448

Test plan:
  * Excuse some assignments
  * Open speedgrader
  * The excused assignments should show they are graded in the dropdown

Change-Id: Idbec25587ebf64574a7c38bf38ddcca22e9ccb6d
Reviewed-on: https://gerrit.instructure.com/58292
Tested-by: Jenkins
Reviewed-by: Spencer Olson <7cc0890d6f1f70810a023e7173eca5724d6c8e49@instructure.com>
QA-Review: Adrian Foong <84c1094366ed084f9dbd0e92a3de1886a73fdc57@instructure.com>
Product-Review: Cameron Matheson <1d572acbfa68c7c6e541c7b840d6b622e5c0dc91@instructure.com>

roxolan/canvas-lms,fronteerio/canvas-lms,tgroshon/canvas-lms,sdeleon28/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,tgroshon/canvas-lms,kyroskoh/canvas-lms,leftplusrightllc/canvas-lms,juoni/canvas-lms,wrdsb/canvas-lms,roxolan/canvas-lms,whalejasmine/canvas-lms,utkarshx/canvas-lms,juoni/canvas-lms,ShreniiNepal/shrenii_lmp,sdeleon28/canvas-lms,leftplusrightllc/canvas-lms,wrdsb/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms,HotChalk/canvas-lms,kyroskoh/canvas-lms,roxolan/canvas-lms,antoniuslin/canvas-lms,fronteerio/canvas-lms,fronteerio/canvas-lms,whalejasmine/canvas-lms,venturehive/canvas-lms,utkarshx/canvas-lms,kyroskoh/canvas-lms,Jyaasa/canvas-lms,efrj/canvas-lms,Rvor/canvas-lms,HotChalk/canvas-lms,ShreniiNepal/shrenii_lmp,skmezanul/canvas-lms,jay3126/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms,sfu/canvas-lms,whalejasmine/canvas-lms,wrdsb/canvas-lms,sfu/canvas-lms,antoniuslin/canvas-lms,utkarshx/canvas-lms,ShreniiNepal/shrenii_lmp,Jyaasa/canvas-lms,roxolan/canvas-lms,greyhwndz/canvas-lms,venturehive/canvas-lms,skmezanul/canvas-lms,Jyaasa/canvas-lms,Rvor/canvas-lms,leftplusrightllc/canvas-lms,skmezanul/canvas-lms,whalejasmine/canvas-lms,HotChalk/canvas-lms,wrdsb/canvas-lms,HotChalk/canvas-lms,antoniuslin/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,utkarshx/canvas-lms,tgroshon/canvas-lms,grahamb/canvas-lms,kyroskoh/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,efrj/canvas-lms,fronteerio/canvas-lms,sdeleon28/canvas-lms,efrj/canvas-lms,djbender/canvas-lms,juoni/canvas-lms,redconfetti/canvas-lms,Rvor/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,greyhwndz/canvas-lms,jay3126/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,greyhwndz/canvas-lms,redconfetti/canvas-lms,jay3126/canvas-lms,sdeleon28/canvas-lms,skmezanul/canvas-lms,leftplusrightllc/canvas-lms,efrj/canvas-lms,sfu/canvas-lms,greyhwndz/canvas-lms,juoni/canvas-lms,Rvor/canvas-lms,Jyaasa/canvas-lms,jay3126/canvas-lms,ShreniiNepal/shrenii_lmp,antoniuslin/canvas-lms,tgroshon/canvas-lms