installing into GCP shared VPC with BYO hosted zone failed with error "failed to create the private managed zone"

    4.20.0-0.nightly-2025-09-01-101753

    Always

1. pre-create the dns private zone in the service project, with the zone's dns name like "<cluster name>.<base domain>" and binding to the shared VPC (see [1]) 
2. activate the service account having minimum permissions, i.e. no permission to bind a private zone to the shared VPC in the host project (see [2] and [3]) 
3. "create install-config" and then insert the interested settings (see [3]) 
4. "create cluster" (see [4])     

    It still tries to create a private zone, which is unexpected.

    The installer should use the pre-configured DNS private zone, rather than try to create a new one.

The working PROW CI test: 
https://qe-private-deck-ci.apps.ci.l2s4.p1.openshiftapps.com/view/gs/qe-private-deck/logs/periodic-ci-openshift-openshift-tests-private-release-4.20-multi-nightly-gcp-ipi-xpn-mini-perm-byo-hosted-zone-arm-f28/1951450651678478336 (4.20.0-0.nightly-multi-2025-07-31-045159)

The problem PROW CI test: 
https://qe-private-deck-ci.apps.ci.l2s4.p1.openshiftapps.com/view/gs/qe-private-deck/logs/periodic-ci-openshift-openshift-tests-private-release-4.20-multi-nightly-gcp-ipi-xpn-mini-perm-byo-hosted-zone-arm-f28/1962707129034870784 (4.20.0-0.nightly-multi-2025-09-01-200104)