Fix definition of TRT extension in IDPVM
Fix the definition of TRT extension in the ID monitoring plots. The old definition used the Trk::TrackInfo::InDetExtensionProcessor
, which is set also for failed extensions (see https://gitlab.cern.ch/atlas/athena/-/blob/main/InnerDetector/InDetRecAlgs/InDetExtensionProcessor/src/InDetExtensionProcessor.cxx).
Adds a new set of monitoring plots plots for TRT extension fraction, specifically for those tracks which have at least one TRT straw hit on its search road, i.e. candidates that could theoretically be extended.