Retrieve shared hits info from TrackParticle in InDetDetailedTrackSelector

In the context of ATLASRECTS-2807, the computation of the shared hit information is going to be moved from the Trk::TrackSummary into the xAOD::TrackParticle creation. This MR anticipates this change by retrieving the corresponding information from the xAOD::TrackParticle in the InDetDetailedTrackSelector tool.

Outputs are checked to be unchanged for q445 test.

FYI @goetz @sroe