A ruling has been issued in a class action lawsuit filed in 2010 against Apple and AT&T, with Apple agreeing to pay $40 to U.S. customers who bought or ordered an iPad 3G before June 7, 2010. Customers who didn’t sign up with AT&T are eligible for a $20/month discount for up to a year on the carrier’s 5GB monthly plan. The lawsuit stems from AT&T advertising an unlimited data plan for iPads, then eliminating the unlimited…