Many Americans in places where sports betting is legal for the first time are beginning to make wagers on the Super Bowl, including some prop bets on the performances of individual athletes. But if the National Football League had its way, bets on things like passing touchdowns for New England Patriots quarterback Tom Brady or rushing yards for Los Angeles Rams running back Todd Gurley would be restricted — or even outlawed as too risky and vulnerable to manipulation or cheating. Proposition bets — also known as prop bets — are less popular during the regular season but gain steam…