fix 6x69 client ID check

src/CommandFormats.hh

@@ -4559,7 +4559,7 @@ struct G_CreateTelepipe_6x68 {
 struct G_NPCControl_6x69 {
   G_UnusedHeader header;
   le_uint16_t state = 0;
-  le_uint16_t npc_client_id = 0;
+  le_uint16_t npc_entity_id = 0;
   le_uint16_t command = 0; // 0 = create follower NPC, 1 = stop acting, 2 = start acting, 3 = create attacker NPC
   le_uint16_t npc_template_index = 0; // Specifies which NPC to create if command == 0 or 3; unused otherwise
 } __packed__;

src/ReceiveSubcommands.cc

@@ -1017,10 +1017,7 @@ static void on_npc_control(shared_ptr<Client> c, uint8_t command, uint8_t flag,
   if (!l->is_game()) {
     throw runtime_error("cannot create NPCs in the lobby");
   }
-  if (cmd.npc_client_id >= 4) {
-    throw runtime_error("NPC client ID is not valid");
-  }
-  if (l->clients[cmd.npc_client_id]) {
+  if ((cmd.npc_entity_id < 4) && l->clients[cmd.npc_entity_id]) {
     throw runtime_error("cannot overwrite existing player with NPC");
   }
   forward_subcommand(c, command, flag, data, size);