Olivia Rodrigo’s dress melted off her body onstage in a surprise costume change during the first night of her ‘Unraveled Tour’ on Friday night. The “Drivers License” singer was performing her song “the cure” at People’s Bank Arena in Hartford, Conn., when artificial rain fell and caused her white sleeveless dress to gradually break apart as she continued singing. Rodrigo, 23, stood onstage as her white dress separated from her outfit, eventually exposing a red corset bodysuit and micro miniskirt underneath, according to fan-shot footage. “First night of the Unraveled Tour was magic!!!! Been planning this show out in my head for the last…