update ar translation
update ar translation

Change-Id: I79c227aa9988c1d2de0d4e712c0d9219fee91776
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/262226
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>

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