[PWGJE Validation] Include track check for leading tracks in jetTrackCollisionQa and fix overcounting of jets in mcJetTrackCollisionQa

[jloemker]

Hey @fkrizek and @GijsvWeelden,

Many thanks for your comments on the jetvalidation task ! I included the following changes.

For the jetTrackCollisionQa (Filip):

• all abs() are changed to fabs()
• the trackSelection check applies now also for the potential leading track
  -> This fixes the number of leading tracks.

For the mcJetTrackCollisionQa (Gijs):

• the loop over detector and particle level jets are now in the .has_mcCollision() loop
• the 'fillMcTrackHistos' function got the collision as additional argument to do a track to collision association
• the jets themselves are now also associated with the collisionId/mcCollisionId
  -> This fixes the over-counting of jets.

Cheers,
Johanna