OCPBUGS-44641: GCP placing *.apps record in wrong managed zone

** The *.apps record is not being placed in the correct DNS Managed Zone.
The existing managed zone should be used only during xpn installs. The ingress
operator was supplied with the incorrect managed zone information.

pkg/asset/manifests/dns.go

@@ -162,12 +162,14 @@ func (d *DNS) Generate(ctx context.Context, dependencies asset.Parents) error {
 
 		// Set the private zone
 		privateZoneID := fmt.Sprintf("%s-private-zone", clusterID.InfraID)
-		zone, err := client.GetDNSZone(ctx, installConfig.Config.GCP.ProjectID, installConfig.Config.ClusterDomain(), false)
-		if err != nil {
-			return errors.Wrapf(err, "failed to get private zone for %q", installConfig.Config.BaseDomain)
-		}
-		if zone != nil {
-			privateZoneID = zone.Name
+		if installConfig.Config.GCP.NetworkProjectID != "" {
+			zone, err := client.GetDNSZone(ctx, installConfig.Config.GCP.ProjectID, installConfig.Config.ClusterDomain(), false)
+			if err != nil {
+				return fmt.Errorf("failed to get private zone for %q: %w", installConfig.Config.BaseDomain, err)
+			}
+			if zone != nil {
+				privateZoneID = zone.Name
+			}
 		}
 		config.Spec.PrivateZone = &configv1.DNSZone{ID: privateZoneID}