Error when removing deleted e-group from ACL

Example:
3 e-groups get added as ACLs. All of these e-groups get deleted at egroups.cern.ch. When trying to remove one of them from the ACL, we get the error `Multipass group does not exist: cern-ldap:xxxx`. You have to remove all of them at once, otherwise it will keep failing.

No files or tests are named. Start by reproducing the ACL removal flow with several deleted e-groups and trace where the “Multipass group does not exist” error is raised; done means removing one deleted e-group succeeds without requiring all deleted groups to be removed at once.

Written by the indexing model from the issue text.