update ar translation
update ar translation

Change-Id: Id47e06c7ce530f796f76e8a624a52afa43aea5d8
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/221588
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms