Add day_of_week_medium_* and day_of_week_short_* for Persian [fa]

Persian was missing data for day_of_week_medium_* and day_of_week_short_*,
resulting in fallbacks to English.

Bug: 6811501
Change-Id: Ib321a964221e451d8b47e2eb025fad8a02f0d5c0
1 file changed