ostree builds that contain openvpn are failing with `error: Installing packages: While applying overrides for pkg openvpn: Could not find group 'openvpn' in group file`

I believe since https://bodhi.fedoraproject.org/updates/FEDORA-2025-5b3a2c4cb3 - which included https://src.fedoraproject.org/rpms/openvpn/c/9335f5fb762fe5d933a431c47b05c880234c49c1?branch=rawhide to switch user and group creation from useradd/groupadd in %pre to a sysusers snippet - Rawhide ostree builds are failing with this error:

DEBUG util.py:461:  error: Installing packages: While applying overrides for pkg openvpn: Could not find group 'openvpn' in group file

this was first encountered in openQA testing of the openvpn update, but it also affected multiple ostrees in today's official Rawhide compose, e.g. Sericea and Silverblue.