Let MoveEffectProperty be None if the move_effect is None
Let MoveEffectProperty be None if the move_effect is None

MoveChangelog.move_effect is None if there is no effect change.
Its .effect should just be None as well.

xfix/pokedex,RK905/pokedex-1,mschex1/pokedex,DaMouse404/pokedex,veekun/pokedex,veekun/pokedex