disable duplicate submission comments
disable duplicate submission comments

fixes CNVS-11958

test plan:

- as an instructor
- go to a submission
- enter a comment
- enter a grade
- click save
- only one instance of the comment should appear

Change-Id: I11f5bdf56bafdbdb40b5cc4ea8bb1e6fc2aca001
Reviewed-on: https://gerrit.instructure.com/36466
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Joel Hough <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@instructure.com>
QA-Review: Steven Shepherd <e794458448443812fb2685675aab3bbd1a3891bc@instructure.com>
Product-Review: Drew Bowman <43bd25f9469d5056946537962fe98ec04e66c401@instructure.com>

kyroskoh/canvas-lms,shidao-fm/canvas-lms,narigone/canvas,Jyaasa/canvas-lms,Jyaasa/canvas-lms,antoniuslin/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,efrj/canvas-lms,instructure/canvas-lms,leftplusrightllc/canvas-lms,snehakachroo1/LSI_replica,HotChalk/canvas-lms,instructure/canvas-lms,samuels410/greatlakes-lms,Rvor/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,juoni/canvas-lms,Rvor/canvas-lms,djbender/canvas-lms,va7map/canvas-lms,jay3126/canvas-lms,instructure/canvas-lms,eCNAP/CANVAS,wye0220/shindig-canvas,efrj/canvas-lms,AndranikMarkosyan/lms,narigone/canvas,grahamb/canvas-lms,ShreniiNepal/shrenii_lmp,redconfetti/canvas-lms,sfu/canvas-lms,antoniuslin/canvas-lms,jay3126/canvas-lms,kyroskoh/canvas-lms,juoni/canvas-lms,kyroskoh/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,wrdsb/canvas-lms,whalejasmine/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,greyhwndz/canvas-lms,venturehive/canvas-lms,dgynn/canvas-lms,matematikk-mooc/canvas-lms,roxolan/canvas-lms,Unow/canvas-lms,wye0220/shindig-canvas,AndranikMarkosyan/lms,djbender/canvas-lms,leftplusrightllc/canvas-lms,narigone/canvas,sfu/canvas-lms,utkarshx/canvas-lms,whalejasmine/canvas-lms,antoniuslin/canvas-lms,venturehive/canvas-lms,narigone/canvas,tgroshon/canvas-lms,wrdsb/canvas-lms,greyhwndz/canvas-lms,HotChalk/canvas-lms,roxolan/canvas-lms,SwinburneOnline/canvas-lms,wrdsb/canvas-lms,snehakachroo1/LSI_replica,instructure/canvas-lms,Unow/canvas-lms,samuels410/greatlakes-lms,samuels410/greatlakes-lms,skmezanul/canvas-lms,ShreniiNepal/shrenii_lmp,gbleydon/canvas-lms,SwinburneOnline/canvas-lms,samuels410/greatlakes-lms,AndranikMarkosyan/lms,sdeleon28/canvas-lms,kyroskoh/canvas-lms,SwinburneOnline/canvas-lms,va7map/canvas-lms,matematikk-mooc/canvas-lms,va7map/canvas-lms,utkarshx/canvas-lms,snehakachroo1/LSI_replica,SwinburneOnline/canvas-lms,tgroshon/canvas-lms,jay3126/canvas-lms,efrj/canvas-lms,juoni/canvas-lms,redconfetti/canvas-lms,whalejasmine/canvas-lms,va7map/canvas-lms,matematikk-mooc/canvas-lms,wrdsb/canvas-lms,matematikk-mooc/canvas-lms,redconfetti/canvas-lms,HotChalk/canvas-lms,Jyaasa/canvas-lms,eCNAP/CANVAS,instructure/canvas-lms,gbleydon/canvas-lms,efrj/canvas-lms,skmezanul/canvas-lms,juoni/canvas-lms,Rvor/canvas-lms,sdeleon28/canvas-lms,skmezanul/canvas-lms,instructure/canvas-lms,dgynn/canvas-lms,roxolan/canvas-lms,roxolan/canvas-lms,shidao-fm/canvas-lms,whalejasmine/canvas-lms,wye0220/shindig-canvas,sdeleon28/canvas-lms,eCNAP/CANVAS,tgroshon/canvas-lms,ShreniiNepal/shrenii_lmp,skmezanul/canvas-lms,sfu/canvas-lms,redconfetti/canvas-lms,grahamb/canvas-lms,Rvor/canvas-lms,snehakachroo1/LSI_replica,Unow/canvas-lms,AndranikMarkosyan/lms,antoniuslin/canvas-lms,eCNAP/CANVAS,ShreniiNepal/shrenii_lmp,sdeleon28/canvas-lms,jay3126/canvas-lms,fronteerio/canvas-lms,tgroshon/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,utkarshx/canvas-lms,sfu/canvas-lms,fronteerio/canvas-lms,shidao-fm/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,greyhwndz/canvas-lms,gbleydon/canvas-lms,utkarshx/canvas-lms,Jyaasa/canvas-lms,venturehive/canvas-lms,shidao-fm/canvas-lms,dgynn/canvas-lms,greyhwndz/canvas-lms,leftplusrightllc/canvas-lms,leftplusrightllc/canvas-lms,dgynn/canvas-lms