removed padding from homework submission dialog
removed padding from homework submission dialog

fixes CNVS-12247

test steps:
- add box as an LTI app
- create an assignment with file upload as a submission option
- log in as student and go to submit assignment
- select box (box.net)
- ensure that there is white padding around the contents of the dialog

note:
I couldn't get rid of the white padding on the very bottom of the dialog
window. This is acceptable white space.

Change-Id: I88eefae6516e5257cabbfb441a7dd64879634bd2
Reviewed-on: https://gerrit.instructure.com/32964
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Eric Berry <b4e131942074b4e4dafdcc14a63e85b7d8e18577@instructure.com>
Product-Review: Eric Berry <b4e131942074b4e4dafdcc14a63e85b7d8e18577@instructure.com>
QA-Review: Eric Berry <b4e131942074b4e4dafdcc14a63e85b7d8e18577@instructure.com>

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