If the logic board looks bone dry, it may not be an issue with the board. Or there could be liquid on the other side of the board (I assume you didn’t take it out of the case). I would definitely say keep it powered off, unplugging the battery would be even better since damage occurs when the liquid comes in contact with POWERED components. And power runs through the board even when it is in a shut down state.
Mostly I just wanted to add that on these newer model of MacBooks, Apple no longer uses liquid damage indicators which turn red. They use UV LCI stickers. Which are black and change color under UV light (although you can generally see if they are triggered even with the naked eye. I can’t find a good picture where I can see these, but there are a few on each edge of the board, and some along the top edge. Give what you’ve said I would be most concerned with liquid in the actual display assembly. You would absolutely be able to tell though if beer had made contact with the board because it leaves residue when it dries.