update ar translation
update ar translation

Change-Id: I614960fa56fe46fe1a54687cd61c2e7c1532d552
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/266637
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