B0TrackerSubAssembly is not defined in ip6 configurations.

[simonge]

The detectors used by ACTS from definitions_craterlake.xml are not included in the epic_ip6 configurations so these cannot be used in reconstruction.

Either the B0TrackerSubAssembly definition should be moved to B0_tracker.xml or definitions_craterlake should be added to the ip6.yml. The former keeps everything to do with the far forward detectors together which the latter keeps the acts detectors together. The comment "ACTS detector volume needs to be built inside out in terms of R." suggesting the order is important so probably best to keep the acts detectors together.