Don't let the user attempt to make moves in drawn study positions

[johndoknjas]

E.g.:

In this study chapter, the game is a stalemate but the user can still try to move the Black king. The study prevents this from happening by only making it a premove, but ideally the user should not be able to try at all. Same story with insufficient mating material positions.

[SergioGlorias]

https://lichess.org/broadcast/fide-world-rapid--blitz-championships-2024--rapid-open-31/round-12/c5SDadI3/SSel8xK4 1 game

[johndoknjas]

@SergioGlorias That one's intentional behaviour though since it's at the ply limit.