fix course_public_description label
fix course_public_description label

test plan: the "Description" box at the bottom of the course
settings page should be labeled properly (the label element should
have a for attribute storing the id of the labeled element)

fixes CNVS-19213

Change-Id: I6c6a9c8762c26fb6401982378bd64c6e3a47555b
Reviewed-on: https://gerrit.instructure.com/50188
Reviewed-by: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
Tested-by: Jenkins
QA-Review: Jahnavi Yetukuri <ed2b2672ccc2e59e56c0615df7f01b579202e014@instructure.com>
Product-Review: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>

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