At a flashy tech conference for a San Francisco security software company this week, a familiar — and probably very pricey — face will make an appearance: former President Barack Obama. After yoga and a networking breakfast Wednesday, attendees will watch Obama spend an hour onstage in Las Vegas with Okta CEO Todd McKinnon at the company’s sixth annual user conference, Oktane. The ex-president is expected to answer questions about leadership, innovation and his time in office.