fix preload notification on stream item assets
fix preload notification on stream item assets

it can't preload until _after_ it knows what the notification_id is

Change-Id: Ice9aef3e1788549a8f0c2d488afe2a0429a6db96
Reviewed-on: https://gerrit.instructure.com/60792
Reviewed-by: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>
Tested-by: Jenkins
Product-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
QA-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>

juoni/canvas-lms,skmezanul/canvas-lms,sfu/canvas-lms,efrj/canvas-lms,skmezanul/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,kyroskoh/canvas-lms,HotChalk/canvas-lms,Rvor/canvas-lms,greyhwndz/canvas-lms,Rvor/canvas-lms,HotChalk/canvas-lms,tgroshon/canvas-lms,whalejasmine/canvas-lms,whalejasmine/canvas-lms,utkarshx/canvas-lms,redconfetti/canvas-lms,fronteerio/canvas-lms,redconfetti/canvas-lms,leftplusrightllc/canvas-lms,tgroshon/canvas-lms,Jyaasa/canvas-lms,utkarshx/canvas-lms,SwinburneOnline/canvas-lms,roxolan/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,juoni/canvas-lms,Jyaasa/canvas-lms,fronteerio/canvas-lms,efrj/canvas-lms,fronteerio/canvas-lms,whalejasmine/canvas-lms,sdeleon28/canvas-lms,Jyaasa/canvas-lms,greyhwndz/canvas-lms,SwinburneOnline/canvas-lms,HotChalk/canvas-lms,skmezanul/canvas-lms,Rvor/canvas-lms,Rvor/canvas-lms,greyhwndz/canvas-lms,antoniuslin/canvas-lms,venturehive/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,leftplusrightllc/canvas-lms,fronteerio/canvas-lms,djbender/canvas-lms,leftplusrightllc/canvas-lms,jay3126/canvas-lms,grahamb/canvas-lms,redconfetti/canvas-lms,djbender/canvas-lms,efrj/canvas-lms,whalejasmine/canvas-lms,sdeleon28/canvas-lms,greyhwndz/canvas-lms,venturehive/canvas-lms,utkarshx/canvas-lms,sfu/canvas-lms,kyroskoh/canvas-lms,sdeleon28/canvas-lms,jay3126/canvas-lms,redconfetti/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,juoni/canvas-lms,efrj/canvas-lms,sdeleon28/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,roxolan/canvas-lms,antoniuslin/canvas-lms,grahamb/canvas-lms,antoniuslin/canvas-lms,jay3126/canvas-lms,grahamb/canvas-lms,kyroskoh/canvas-lms,djbender/canvas-lms,kyroskoh/canvas-lms,tgroshon/canvas-lms,roxolan/canvas-lms,utkarshx/canvas-lms,leftplusrightllc/canvas-lms,skmezanul/canvas-lms,sfu/canvas-lms,juoni/canvas-lms,venturehive/canvas-lms,antoniuslin/canvas-lms,Jyaasa/canvas-lms,tgroshon/canvas-lms,jay3126/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms