Facebook is undermining its revenue model with its new approach to video, but it could pay off in the long run. — For years, Facebook has denied that it’s a media company. Sheryl Sandberg, COO; Chris Cox, CPO; and Mark Zuckerberg, cofounder and CEO, have all flatly said that Facebook is a tech company. But over the last few years, that position has become less tenable. Now, it seems that Facebook has…