Human can still play moves after the game is won by AI

[AyushShahh]

This bug is probably a side-product while solving #4 in PR #8
Only happens when AI has won and there are still unused squares in the playboard

As you can see in this gif, if you play a move and you don't win then you cannot play more moves. But if you play a move and you win then you can keep playing moves until there are no squares left to play. Also after each move, human score will increment by one