send user_image only on public lti launches
send user_image only on public lti launches

test plan:
  - change a tool's privacy level to anonymous
  - tool launch should not have user_image
  - change a tool's privacy level to public
  - tool launch should have user_image

fixes PLAT-708

Change-Id: Iccca705fd3e5c5385ae63897e49d9c67d46f62d7
Reviewed-on: https://gerrit.instructure.com/43633
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Product-Review: Bracken Mosbacker <48b846001bca4166dc3fb7711563afc17525921e@instructure.com>
Reviewed-by: Bracken Mosbacker <48b846001bca4166dc3fb7711563afc17525921e@instructure.com>
QA-Review: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>

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