public data overlays are not accessible via API

this shouldn't return empty list: https://minerva-dev.lcsb.uni.lu/minerva//api//projects/PDmap_Dec15_main/overlays/?publicOverlay=True

created branch 332-public-data-overlays-are-not-accessible-via-api

mentioned in merge request !220 (closed)

resolved here 5e65fe5c

closed