Core/TicketMgr: Remove a memory leak in RemoveTicket. Spotted by Subv

src/server/game/Tickets/TicketMgr.cpp

@@ -301,6 +301,7 @@ void TicketMgr::RemoveTicket(uint32 ticketId)
     {
         ticket->DeleteFromDB();
         _ticketList.erase(ticketId);
+        delete ticket;
     }
 }