Cook noodles according to package directions. Add seasoning packets and drain off most liquid; set aside. In a 10" skillet over medium heat, in hot oil, cook vegetables and garlic 2 minutes, stirring often. Stir in mushroom soup, mozzarella cheese, milk, and black pepper. Cook until cheese melts, stirring occasionally. Stir in reserved noodles and tuna. Heat through, stirring occasionally.