I believe the correct fix would need to be in the docker image definition or the source repo. However, if you're looking for a quick/temporary fix the following worked for me:
1) find all package-lock.json files in the docker file system
find /var/lib/docker -name 'package-lock.json'
2) Remove the ones that are associated with shinobi:
eg.
rm /var/lib/docker/btrfs/subvolumes/<some-volumenhash>/opt/shinobi/package-lock.json
3) In the Unraid 'Docker' tab, enable the 'Advanced view' (top right), and 'Force Update' the shinobi pro container