By Chris Mannix Throughout a season of uncertainty for the Sixers, the star center has been the team’s unshakable anchor, remaining steadfast in his focus on bringing a championship to Philadelphia. The black Sprinter van had just made the turn out of the CBS Studios lot when Joel Embiid made an announcement. “I don’t want to be an actor,” the Sixers star says. Last fall, he linked up with WME, the powerful talent agency, in part to figure out what his post-playing career could look like. An hour on the set of The Late, Late Show With James Corden running through a sketch during an off day in …