RICHMOND, Va. -- Virginia doctor and poison expert Dr. Avery Michienzi has a warning for anyone who buys mushroom gummies sold at smoke shops and convenience stores."I would be very, very cautious with what you're buying," Dr. Michienzi said. "Know that even if the label says it's one thing, there's a very, very good chance that it's not what it says it is.Michienzi, an assistant professor of emergency medicine at the University of Virginia and …