If you’re in the bubbly business in the Aube (the southern region in France’s Champagne-Ardenne), then you have to make peace with the fact that, compared with the popular Épernay and Ay to the north, you’re basically the red-headed stepchild of Champagne. Unless you’re Emmanuel Lassaigne, who crafts the bubbly at Champagne Jacques Lassaigne. In…