VP1TrackSystems: Fix for missing Muon chambers as reported in ATLASVPONE-668
As reported in ATLASVPONE-668, active muon chambers are no longer shown
@jojungge and I tracked this down to !68816 (merged) - the fix here broke the mechanism which VP1 used to link chambers with measurements and the displayed chambers. This fix restores this link.
Closes ATLASVPONE-668
cc @ncalace