Declare thread-unsafe components used exclusivly by LAr Electronic Calibration as such

Several algorithms and tools in LArCalorimeter/LArCalibUtils are inherently incompatible with athenaMT because they do almost all of their work in stop() and sometimes modify objects in the DetectorStore.

This MR declares these thread-unsafe components as such so that the thread-safety checker passes.

Note that the code in question is internal to the LAr Electronic Calibration procedure and not executed in any other production nor tested in the CI.