update ar translation
update ar translation

Change-Id: Ie03d908677c33745843bd18972a17d03199563a6
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/255430
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms