os-images-info unit sometimes times-out (takes more than 10 minutes)

in https://gitlab.com/sylva-projects/sylva-core/-/jobs/12207140870 we have a case where the os-images-info Job hasn't finished in the alloted 10 minutes before sylvactl timesout

increasing to 10 minutes (!6155 (merged)) isn't sufficient

we'll need to understand why this script takes that long