Jennette McCurdy’s new memoir “I’m Glad My Mom Died” finds the former Nickelodeon star getting brutally honest with her feelings on Ariana Grande, the music icon who briefly starred with McCurdy on the “iCarly” and “Victorious” spinoff series “Sam & Cat.” Grande’s pop star career started taking off during the filming of the show, which only ran for a single season on Nickelodeon.