fix outcomes sidebar in ie8
fix outcomes sidebar in ie8

fixes #11521

the sidebar was not rendering correctly in ie8 due to incorrect usage of
the array splice() function.

test plan:
- created multiple outcome groups with tested outcome groups with outcomes
- click back and forth between different group folders
- they should render correctly
- delete one of the nested groups with outcomes
- it should work and render correctly

Change-Id: I3f821e908bd3a132048b823de4b39ffad1810fc2
Reviewed-on: https://gerrit.instructure.com/15076
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Stanley Stuart <d3942c3cf0aa13de8a95b690bdc33eab29ac4e73@instructure.com>
Reviewed-by: Zach Pendleton <514dbb4d54d4f29e454990df7d075678f43f92aa@instructure.com>

Jyaasa/canvas-lms,arrivu/hiring-site,instructure/canvas-lms,nditech/red-innovadores-lms,loganrun/pincan,arrivu/hiring-site,redconfetti/canvas-lms,Unow/ins,instructure/canvas-lms,sfu/canvas-lms,arrivu/hoodemo,jay3126/canvas-lms,kyroskoh/canvas-lms,tgroshon/canvas-lms,greyhwndz/canvas-lms,instructure/canvas-lms,efrj/canvas-lms,jay3126/canvas-lms,narigone/canvas,HotChalk/canvas-lms,wrdsb/canvas-lms,sli7246/canvas_branch,utkarshx/canvas-lms,ShreniiNepal/shrenii_lmp,greyhwndz/canvas-lms,Unow/canvas-lms,arrivu/hoodemo,wimemx/Canvas,arrivu/qibla-ecampus,dgynn/canvas-lms,ShreniiNepal/shrenii_lmp,skmezanul/canvas-lms,loganrun/pincan,arrivu/qibla-ecampus,arrivu/jigsaw-lms,sli7246/canvas_branch,fronteerio/canvas-lms,SwinburneOnline/canvas-lms,shidao-fm/canvas-lms,Rvor/canvas-lms,ShreniiNepal/shrenii_lmp,Rvor/canvas-lms,instructure/canvas-lms,whalejasmine/canvas-lms,wrdsb/canvas-lms,matematikk-mooc/canvas-lms,venturehive/canvas-lms,arrivu/hoodemo,Jyaasa/canvas-lms,snehakachroo1/LSI_replica,AndranikMarkosyan/lms,sfu/canvas-lms,snehakachroo1/LSI_replica,Unow/canvas-lms,arrivu/arrivu-lms,kyroskoh/canvas-lms,AndranikMarkosyan/lms,arrivu/arrivu-lms,instructure/canvas-lms,HotChalk/canvas-lms,dgynn/canvas-lms,usmschuck/canvas,kyroskoh/canvas-lms,grahamb/canvas-lms,parbros/red-innovadores-lms,sfu/canvas-lms,narigone/canvas,leftplusrightllc/canvas-lms,roxolan/canvas-lms,antoniuslin/canvas-lms,narigone/canvas,djbender/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,redconfetti/canvas-lms,utkarshx/canvas-lms,utkarshx/canvas-lms,juoni/canvas-lms,parbros/red-innovadores-lms,roxolan/canvas-lms,grahamb/canvas-lms,matematikk-mooc/canvas-lms,shidao-fm/canvas-lms,narigone/canvas,utkarshx/canvas-lms,AndranikMarkosyan/lms,snehakachroo1/LSI_replica,wye0220/shindig-canvas,djbender/canvas-lms,nditech/red-innovadores-lms,wimemx/Canvas,sdeleon28/canvas-lms,usmschuck/canvas,eCNAP/CANVAS,rup/Tarrax,nditech/red-innovadores-lms,landonwilkins/canvas-lms,rup/Tarrax,usmschuck/canvas,whalejasmine/canvas-lms,antoniuslin/canvas-lms,snehakachroo1/LSI_replica,arrivu/hiring-site,gbleydon/canvas-lms,HotChalk/canvas-lms,antoniuslin/canvas-lms,wrdsb/canvas-lms,venturehive/canvas-lms,arrivu/jigsaw-lms,sdeleon28/canvas-lms,greyhwndz/canvas-lms,kyroskoh/canvas-lms,va7map/canvas-lms,leftplusrightllc/canvas-lms,Unow/ins,whalejasmine/canvas-lms,matematikk-mooc/canvas-lms,va7map/canvas-lms,venturehive/canvas-lms,va7map/canvas-lms,juoni/canvas-lms,Rvor/canvas-lms,leftplusrightllc/canvas-lms,SwinburneOnline/canvas-lms,eCNAP/CANVAS,SwinburneOnline/canvas-lms,Jyaasa/canvas-lms,wimemx/Canvas,dgynn/canvas-lms,arrivu/qibla-ecampus,skmezanul/canvas-lms,AndranikMarkosyan/lms,samuels410/greatlakes-lms,va7map/canvas-lms,landonwilkins/canvas-lms,redconfetti/canvas-lms,Jyaasa/canvas-lms,efrj/canvas-lms,gbleydon/canvas-lms,wrdsb/canvas-lms,leftplusrightllc/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,sli7246/canvas_branch,grahamb/canvas-lms,wye0220/shindig-canvas,juoni/canvas-lms,greyhwndz/canvas-lms,dgynn/canvas-lms,fronteerio/canvas-lms,landonwilkins/canvas-lms,tgroshon/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,rup/Tarrax,instructure/canvas-lms,merichar/canvas-lms,shidao-fm/canvas-lms,sdeleon28/canvas-lms,djbender/canvas-lms,eCNAP/CANVAS,usmschuck/canvas,eCNAP/CANVAS,gbleydon/canvas-lms,nditech/red-innovadores-lms,wye0220/shindig-canvas,juoni/canvas-lms,jay3126/canvas-lms,tgroshon/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,samuels410/greatlakes-lms,grahamb/canvas-lms,merichar/canvas-lms,efrj/canvas-lms,samuels410/greatlakes-lms,fronteerio/canvas-lms,samuels410/greatlakes-lms,fronteerio/canvas-lms,jay3126/canvas-lms,efrj/canvas-lms,antoniuslin/canvas-lms,landonwilkins/canvas-lms,sfu/canvas-lms,ShreniiNepal/shrenii_lmp,Rvor/canvas-lms,skmezanul/canvas-lms,whalejasmine/canvas-lms,arrivu/arrivu-lms,parbros/red-innovadores-lms,merichar/canvas-lms,tgroshon/canvas-lms,redconfetti/canvas-lms,sdeleon28/canvas-lms,loganrun/pincan,matematikk-mooc/canvas-lms,Unow/canvas-lms,shidao-fm/canvas-lms,sfu/canvas-lms,Unow/ins,skmezanul/canvas-lms,arrivu/jigsaw-lms