It’s last swim for the troubled DC Extended Universe, planned for an overall rethink, as Jason Momoa returns as the King of Atlantis in “Aquaman and the Lost Kingdom.” In some important ways, the sequel laps the original. In others, it — and its mega-franchise — seem destined to sink without a ripple. When last we saw Arthur Curry (Momoa), he was lying face-down drunk in a puddle in the jokey…