Why Broadway's SpongeBob gave up pizza and booze

SpongeBob loves Scrub Daddy. And before Nickelodeon flips out over that unauthorized endorsement, please note that it's Ethan Slater -- Broadway's SpongeBob -- who's doing the endorsing. "Scrub Daddy was on 'Shark Tank,'" he tells The Post about his favorite kitchen tool. "It's a smiley-face sponge that's easy to hold, and you can really scrub...