Spencer Pratt and Heidi Montag’s six-year-old son is set to launch his own YouTube channel. The loved-up couple have revealed that they’re supporting their son, Gunner Pratt, as he prepares to launch his YouTube career. Heidi, 37 – who also has Ryker, 19 months, with Spencer – told E! News: “Gunner is gonna come out with his own YouTube channel,” Heidi told E! News in an exclusive interview last month. “We’re actually working on it.” Gunner has actually wanted to launch his own channel for more than a year. Spencer said: “No momager-dadager. But he watches all these kids on YouTube. So he sees…