don't fail when copying wiki pages with no title
don't fail when copying wiki pages with no title

wiki pages with no title exist from old external
migrations that use to allow this to happen, this
change prevents course copies from failing when
trying to copy those wiki pages

closes #4801

Change-Id: I50389f30e4553178c04fafb634a5e023fb4e836a
Reviewed-on: https://gerrit.instructure.com/4107
Tested-by: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@instructure.com>
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Reviewed-by: Brian Palmer <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@instructure.com>

AndranikMarkosyan/lms,djbender/canvas-lms,kyroskoh/canvas-lms,greyhwndz/canvas-lms,arrivu/hiring-site,sfu/canvas-lms,parbros/red-innovadores-lms,sfu/canvas-lms,shidao-fm/canvas-lms,roxolan/canvas-lms,ShreniiNepal/shrenii_lmp,usmschuck/canvas,instructure/canvas-lms,eCNAP/CANVAS,shidao-fm/canvas-lms,landonwilkins/canvas-lms,roxolan/canvas-lms,sfu/canvas-lms,rup/Tarrax,dgynn/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,greyhwndz/canvas-lms,em2/canvas-lms,antoniuslin/canvas-lms,narigone/canvas,sfu/canvas-lms,matematikk-mooc/canvas-lms,wimemx/Canvas,eCNAP/CANVAS,instructure/canvas-lms,landonwilkins/canvas-lms,Unow/canvas-lms,HotChalk/canvas-lms,parbros/red-innovadores-lms,gbleydon/canvas-lms,wimemx/Canvas,kyroskoh/canvas-lms,skmezanul/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,jay3126/canvas-lms,leftplusrightllc/canvas-lms,Jyaasa/canvas-lms,arrivu/hoodemo,ankithbti/canvas_lms,djbender/canvas-lms,antoniuslin/canvas-lms,narigone/canvas,djbender/canvas-lms,Jyaasa/canvas-lms,antoniuslin/canvas-lms,ottenhoff/canvas-lms,greyhwndz/canvas-lms,fronteerio/canvas-lms,usmschuck/canvas,efrj/canvas-lms,Unow/ins,whalejasmine/canvas-lms,instructure/canvas-lms,gbleydon/canvas-lms,juoni/canvas-lms,Unow/canvas-lms,HotChalk/canvas-lms,HotChalk/canvas-lms,shidao-fm/canvas-lms,arrivu/jigsaw-lms,rup/Tarrax,wye0220/shindig-canvas,juoni/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,sdeleon28/canvas-lms,usmschuck/canvas,Rvor/canvas-lms,Jyaasa/canvas-lms,skmezanul/canvas-lms,greyhwndz/canvas-lms,snehakachroo1/LSI_replica,parbros/red-innovadores-lms,samuels410/greatlakes-lms,AndranikMarkosyan/lms,usmschuck/canvas,wye0220/shindig-canvas,tgroshon/canvas-lms,SwinburneOnline/canvas-lms,Rvor/canvas-lms,kyroskoh/canvas-lms,whalejasmine/canvas-lms,arrivu/qibla-ecampus,fronteerio/canvas-lms,wrdsb/canvas-lms,samuels410/greatlakes-lms,venturehive/canvas-lms,samuels410/greatlakes-lms,tgroshon/canvas-lms,arrivu/jigsaw-lms,faraazkhan/canvas,matematikk-mooc/canvas-lms,ankithbti/canvas_lms,roxolan/canvas-lms,SwinburneOnline/canvas-lms,juoni/canvas-lms,wrdsb/canvas-lms,arrivu/arrivu-lms,sfu/canvas-lms,snehakachroo1/LSI_replica,loganrun/pincan,matematikk-mooc/canvas-lms,tgroshon/canvas-lms,antoniuslin/canvas-lms,arrivu/jigsaw-lms,icelab/canvas,AndranikMarkosyan/lms,venturehive/canvas-lms,sli7246/canvas_branch,arrivu/arrivu-lms,fronteerio/canvas-lms,arrivu/arrivu-lms,redconfetti/canvas-lms,utkarshx/canvas-lms,sli7246/canvas_branch,icelab/canvas,grahamb/canvas-lms,narigone/canvas,merichar/canvas-lms,ShreniiNepal/shrenii_lmp,grahamb/canvas-lms,Rvor/canvas-lms,va7map/canvas-lms,nditech/red-innovadores-lms,kyroskoh/canvas-lms,instructure/canvas-lms,whalejasmine/canvas-lms,dgynn/canvas-lms,AndranikMarkosyan/lms,redconfetti/canvas-lms,eCNAP/CANVAS,efrj/canvas-lms,grahamb/canvas-lms,ankithbti/canvas_lms,redconfetti/canvas-lms,Unow/ins,loganrun/pincan,arrivu/hoodemo,nditech/red-innovadores-lms,matematikk-mooc/canvas-lms,samuels410/greatlakes-lms,faraazkhan/canvas,nditech/red-innovadores-lms,landonwilkins/canvas-lms,em2/canvas-lms,ShreniiNepal/shrenii_lmp,loganrun/pincan,gbleydon/canvas-lms,venturehive/canvas-lms,SwinburneOnline/canvas-lms,leftplusrightllc/canvas-lms,skmezanul/canvas-lms,narigone/canvas,eCNAP/CANVAS,venturehive/canvas-lms,juoni/canvas-lms,arrivu/hiring-site,sdeleon28/canvas-lms,fronteerio/canvas-lms,leftplusrightllc/canvas-lms,snehakachroo1/LSI_replica,sfu/canvas-lms,snehakachroo1/LSI_replica,Unow/ins,djbender/canvas-lms,efrj/canvas-lms,efrj/canvas-lms,wrdsb/canvas-lms,redconfetti/canvas-lms,shidao-fm/canvas-lms,leftplusrightllc/canvas-lms,va7map/canvas-lms,utkarshx/canvas-lms,arrivu/qibla-ecampus,jay3126/canvas-lms,roxolan/canvas-lms,icelab/canvas,Unow/canvas-lms,wye0220/shindig-canvas,merichar/canvas-lms,jay3126/canvas-lms,wrdsb/canvas-lms,utkarshx/canvas-lms,em2/canvas-lms,HotChalk/canvas-lms,rup/Tarrax,Jyaasa/canvas-lms,faraazkhan/canvas,arrivu/hoodemo,ottenhoff/canvas-lms,skmezanul/canvas-lms,sdeleon28/canvas-lms,SwinburneOnline/canvas-lms,arrivu/hiring-site,merichar/canvas-lms,va7map/canvas-lms,nditech/red-innovadores-lms,utkarshx/canvas-lms,grahamb/canvas-lms,arrivu/qibla-ecampus,sli7246/canvas_branch,sdeleon28/canvas-lms,jay3126/canvas-lms,ShreniiNepal/shrenii_lmp,whalejasmine/canvas-lms,landonwilkins/canvas-lms,wimemx/Canvas,ottenhoff/canvas-lms,Rvor/canvas-lms,tgroshon/canvas-lms,dgynn/canvas-lms,va7map/canvas-lms