Mark Sanchez says he and Jamie-Lynn Sigler are “just friends” — but it looks like they’re dating. The Jets quarterback and the “Sopranos” star were out together again on Saturday, at Canal Room for “Back to the ’80s” with tribute band Rubix Kube. The two were hanging out in the VIP area with Lance Bass during the two-hour show, then joined the band onstage to sing Bon Jovi’s “Living on a Prayer” for the finale. Said one spy, “The whole place was screaming, ‘New York Jets! New York Jets!’ “