Harvard-born 3-D greeting card startup LovePop Cards will debut on ABC's "Shark Tank" TV show on Dec. 11. The startup's co-founders faced the "Sharks," which include investor Mark Cuban, and pitched their business. LovePop landed $2.6 million in equity funding out of a planned $3.4 million goal, according to a Nov. 25 regulatory filing with the Securities and Exchange Commission. The investment marks the company's first significant funding round, after its intricate special occasion cards started…