update ar translation
update ar translation

Change-Id: Ib5d01f2589d84265f47a9e51629a801d997f6479
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/279896
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