[Bug] Fix Berserk and Anger Shell from crashing the game when pokemon…

… is forced to switch out (pagefaultgames#1699)

* fix PostDefendHpGatedStatChangeAbAttr crashing the game

* remove new line

* refactor condition

* refactor condition

src/data/ability.ts

@@ -677,7 +677,9 @@ export class PostDefendHpGatedStatChangeAbAttr extends PostDefendAbAttr {
   applyPostDefend(pokemon: Pokemon, passive: boolean, attacker: Pokemon, move: Move, hitResult: HitResult, args: any[]): boolean {
     const hpGateFlat: integer = Math.ceil(pokemon.getMaxHp() * this.hpGate);
     const lastAttackReceived = pokemon.turnData.attacksReceived[pokemon.turnData.attacksReceived.length - 1];
-    if (this.condition(pokemon, attacker, move) && (pokemon.hp <= hpGateFlat && (pokemon.hp + lastAttackReceived.damage) > hpGateFlat)) {
+    const damageReceived = lastAttackReceived?.damage || 0;
+
+    if (this.condition(pokemon, attacker, move) && (pokemon.hp <= hpGateFlat && (pokemon.hp + damageReceived) > hpGateFlat)) {
       pokemon.scene.unshiftPhase(new StatChangePhase(pokemon.scene, (this.selfTarget ? pokemon : attacker).getBattlerIndex(), true, this.stats, this.levels));
       return true;
     }