Openstack DCN Ceph Upgrade - ceph-ansible's cephadm-adopt task 'Update the placement of radosgw hosts' failing when multiple subnets are defined

Issue

The following command from Step 7: Configure the Red Hat Ceph Storage nodes to use cephadm

 openstack overcloud external-upgrade run \
    --skip-tags ceph_ansible_remote_tmp \
    --stack <stack> \
    --tags cephadm_adopt

Fails with:

2025-01-09 11:43:33,111 p=135372 u=root n=ansible | TASK [Update the placement of radosgw hosts] ***********************************
2025-01-09 11:43:33,111 p=135372 u=root n=ansible | Thursday 09 January 2025 11:43:33 -0500 (0:00:00.131) 0:01:11.588 ******
2025-01-09 11:43:39,305 p=135372 u=root n=ansible | An exception occurred during task execution. To see the full traceback, use -vvv. The error was: Error EINVAL: Cannot parse network '192.168.1.0/24,192.168.2.0/24,192.168.3.0/24' does not appear to be an IPv4 or IPv6 network

The overcloud-deploy/<stack>/config-download/<stack>/ceph-ansible/group_vars/rgws.yml file contains

radosgw_address_block: 192.168.1.0/24,192.168.2.0/24,192.168.3.0/24