Avoid using ConcurrencyFlags in Trigger
AthenaCommon.ConcurrencyFlags are not valid at python-configuration time in online HLT and should be avoided anywhere in Trigger. The Trigger configuration cannot depend on them, since the number of threads/slots is configured from OKS in C++. It can also differ between nodes in the farm and between runs, so changing job configuration based on these numbers should be forbidden in Trigger.
This MR is removing trivial cases where the use was not actually needed (discovered thanks to ATR-20524), and fixing TriggerFlags.doMT stored value.
Also fixing the stored value of OnlineFlags.partitionName even though I couldn't use it here, as explained in the comment in TriggerFlags.