Tack track curvature directly from Delphes and don't recompute it from pT

[EmanuelPerez]

BEGINRELEASENOTES

• The track's omega is taken directly from the curvature of the delphes track, instead of recomputing it from the track pT. Converting the curvature to pT and then back to omega leads to a worse numerical precision.

ENDRELEASENOTES

An example is shown in the attached plots. They show the pull of the reconstructed position of a displaced vertex in some B physics process, running the very same code over the same events, the only difference being the definition of the track's omega in DelphesEDM4HepConverter::convertTrack. With the current code, the pull shows some non gaussian tails, which are absent if omega is taken directly from the curvature of Delphes.

[tmadlener]

CI based on nightlies seems to be broken currently due to https://github.com/key4hep/key4hep-spack/issues/540. However, since things build on top of the current release I will still merge this in order to make a new tag.

[tmadlener]

@EmanuelPerez thanks.