Within the rich cinematic tradition of gender-bending sex comedies, films about high schoolers posing as male or female coeds have been on quite a run since the 1980s. But the subgenre that gave us Just One of the Guys and She’s the Man has long been in need of a timely hit — which is exactly what first-time feature director Siobhan McCarthy is hoping to score with She’s The He.Following in the footsteps of 2023’s Bottoms — which parodied high s…