A Manhattan pizzeria worker was mauled by an irate customer’s pit bull during a vicious beatdown late Monday that was sparked because the dog wasn’t allowed in the shop, cops and sources said. The 50-year-old worker at Roma Pizzeria clung to life Tuesday as the pit bull’s owner Tyshaun Watson, 35, was slapped with an attempted murder charge for allegedly pummeling the employee — later saying he was “sorry” when he was cuffed, cops said. Surveillance video captured a merciless attack by Watson after he walked into the Flatiron eatery along Fifth Avenue with his pit bull about 10 p.m.,...