Lola Tung wants to make one thing abundantly clear: She will always be Team Belly. Tung has given new life to Isabel “Belly” Conklin, the teenage heroine who finds herself entangled in a messy love triangle with the sons of her mother’s best friend, in Jenny Han’s The Summer I Turned Pretty, which returns Friday for its sophomore season on Prime Video. It’s a breakout role that has transformed the acting newcomer from wide-eyed college freshman into bona fide leading lady.