TrigCost: Handle missing thread id in monitorROS
After !53964 (merged) in two nightly tests an error was observed:
TrigCostMonitor/src/TrigCostSvc.cxx:183 (StatusCode TrigCostSvc::monitorROS(const EventContext&,
robmonitor::ROBDataMonitorStruct)): code FAILURE: m_threadToAlgMap.find(acc, std::this_thread::get_id())
[415453,8666587,t:1648247170.552239150,l:200,b:2843]
It indicates that the data from ROS were requested before registering any algorithms in Cost. The error is hard to reproduce offline. This MR will just prevent the error, instead, a warning will be printed.
Related to ATR-25698