restore styling for completed events in calendar
restore styling for completed events in calendar

fixes CNVS-25242

test-plan:
 [as a student]
 - have an assignment with a due date so it shows up on the calendar
 - make a submission for the assignment
 - look at the assignment on the calendar
 - it should show dimmed and with a strikethrough

Change-Id: I24e3b689138028355fb3eb69c5bec22865f7de3d
Reviewed-on: https://gerrit.instructure.com/67647
Reviewed-by: Matthew Wheeler <ce71fbafda91d6c8f12582e1837687d5fe592dd9@instructure.com>
QA-Review: Derek Hansen <cb1116771307a93b98b6babf698410ed3846296d@instructure.com>
Tested-by: Jenkins
Product-Review: Rob Orton <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@instructure.com>

sfu/canvas-lms,roxolan/canvas-lms,sfu/canvas-lms,leftplusrightllc/canvas-lms,HotChalk/canvas-lms,SwinburneOnline/canvas-lms,leftplusrightllc/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,venturehive/canvas-lms,roxolan/canvas-lms,redconfetti/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,redconfetti/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms,grahamb/canvas-lms,leftplusrightllc/canvas-lms,fronteerio/canvas-lms,roxolan/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,leftplusrightllc/canvas-lms,fronteerio/canvas-lms,roxolan/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,redconfetti/canvas-lms