transfer focus to opened region in .element_toggler
transfer focus to opened region in .element_toggler

this makes it so if you have an .element_toggler
it will try to focus on the first child tubbable
element within the region in addition to the region
itself.  For example: the first <input> inside
a hidden <form>

Change-Id: I3e85f1f549504cbb528f1653736457d04b4cc7bf
Reviewed-on: https://gerrit.instructure.com/16107
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Zach Pendleton <514dbb4d54d4f29e454990df7d075678f43f92aa@instructure.com>
QA-Review: Amber Taniuchi <ef4bfd1e6d278f6bc7d4a478f02be2cb9581a0a5@instructure.com>

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