feat: Update event time check in gacha controller

Update the event time check in the gacha controller to reflect the correct month and date for the event. This ensures that the Europe gacha pool is only available during the specified event time.

app/src/controller/princess/gacha.js

@@ -186,7 +186,7 @@ async function gacha(context, { match, pickup, ensure = false, europe = false })
   const now = moment();
   const month = now.month() + 1;
   const date = now.date();
-  const isEventTime = month === 5 && (date >= 11 && date <= 15);
+  const isEventTime = month === 6 && date >= 9 && date <= 11;
 
   // 只有 12/31~1/1 這兩天才會開放歐洲轉蛋池
   if (europe && !isEventTime) {