GetActivityBossDataRequest stub to prevent softlock when entering Co-op

AscNet.GameServer/Handlers/BossModule.cs

@@ -15,6 +15,17 @@ namespace AscNet.GameServer.Handlers
     {
         public int Code;
     }
+
+    [MessagePackObject(true)]
+    public class GetActivityBossDataRequest
+    {
+    }
+    
+    [MessagePackObject(true)]
+    public class GetActivityBossDataResponse
+    {
+        public int Code;
+    }
 #pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
     #endregion
 
@@ -25,5 +36,11 @@ namespace AscNet.GameServer.Handlers
         {
             session.SendResponse(new BossSingleRankInfoResponse() { Code = 1 }, packet.Id);
         }
+
+        [RequestPacketHandler("GetActivityBossDataRequest")]
+        public static void GetActivityBossDataRequestHandler(Session session, Packet.Request packet)
+        {
+            session.SendResponse(new GetActivityBossDataResponse() { Code = 1 }, packet.Id);
+        }
     }
 }