fix crash caused by function not being async

src/model/card_behaviour.py

@@ -1,6 +1,6 @@
 from typing import TYPE_CHECKING, Awaitable, Optional
 from model.card_validator import EffectParser
-from model.card import Card, Effect, EffectType, CardEffects, EffectTimes, CardType
+from model.card import Effect, EffectType, CardEffects, EffectTimes, CardType
 
 
 if TYPE_CHECKING:
@@ -55,7 +55,7 @@ async def effect_heal(effect: Effect, turn: "Turn", _target: str):
     return True
 
 
-def effect_prepare(_effect: Effect, turn: "Turn", target: str):
+async def effect_prepare(_effect: Effect, turn: "Turn", target: str):
     return turn.prepare(target)