After merging checking if structural readers are not used for list nodes,
it uncovered issue in VppIoamModule.

The issue is that PotProfileSet is keyed node, therefore structuralReader cannot be used for it,
at least not before HONEYCOMB-344 is resolved.

In the mean time, please provide customizer instead, that will return static collection of keys.
Because of this issue, ioam plugin will be temporary excluded from build in hc2vpp-aggregator