Added a track summary to the tracks returned by MuonTrackSteering::findTracks

In order to remove unnecessary copying of track summaries, in particular those for const-tracks, it is necessary to avoid the creation of track summaries within TrackParticleCreatorTool. For this to work we need to ensure that the tracks already have a track summary and that the tool tool uses those already owned by the track. We would like to ensure that the track has already a summary so that, in the future, the TrackParticleCreatorTool does not need to make a copy and just use the summary from the track.