Clean up un-needed TRTPreProcessingCfg for TRTExtension config
TRTPreProcessingCfg
is already scheduled in https://gitlab.cern.ch/atlas/athena/-/blob/main/InnerDetector/InDetConfig/python/TrackRecoConfig.py?ref_type=heads#L175
Removing it from the TRTExtension configs
FYI @fatsai