Millie Bobby Brown is back as Sherlock Holmes’ kid sister in “Enola Holmes 2,” which is as slick and fun as the 2020 original, even if the stakes this time around seem considerably lower. Enola spends just as much time cracking cases as she does cracking wise for the viewers at home, staring into the camera and winking, deadpanning or rolling her eyes at whatever situation she’s thrust into, as much a Bueller as she is a Holmes. Brown gets it and director Henry Bradbeer does too, and all the sidetalk is there to let you know that it’s OK, nothing all that serious happening on screen, and there…