Trigger: Handling of magnetic field changes

Update various job options to work with the new magnetic field conditions algorithm and retire the use of the AtlasFieldSvc (ATR-21277). Currently we need to run with

AtlasFieldMapCondAlg.UseMapsFromCOOL = False

because loading the field map names from COOL does not work during the start transition. Alternatively we could read the maps from COOL on the first event, but this would entail a memory penalty when forking. Map names never/rarely change. But if they do and if we haven't changed to using them from COOL we need to make sure they are updated also in the job option parameters.

Also redesign the magFieldToggle test. It now uses a dummy algorithm to check the field status instead of the full physics menu. This is currently the only way this can be tested because we need to use 3 different run numbers. Using a full physics menu would require valid information for all these three runs in COOL (e.g. Beamspot). Might look into fixing this at a later point.

Requires !36068 (merged) to be merged first.