removing what appears to be a left-over from the previous experiment.
Based on further conversation with the Artifactory plugin developers, revisiting this extension point.

This is a breaking change, but this extension point was added very recently, and it's based on the input from Artifactory plugin, so there's not much point in keeping one that doesn't serve the intended use case.
not sure why this works locally, but when run on Jenkins it complains

... probably because it's split in two lines