[Backup/Restore] Postgresql wrongly references Endpoint instead of Service in k8s

Looking into restore code for kubernetes, I can see in [these lines](https://github.com/canonical/postgresql-k8s-operator/blob/b0641ccb1926a05fcd6b53febf26c5299384b452/src/backups.py#L564-L575) that we must delete `patroni--config` endpoint to restore from backup.

However, Patroni coming from latest 14.9, channel=14/edge, does not exist as an endpoint. It exists as a `Service`.
That section should fail during restore process.

Start in src/backups.py at lines 564-575 and trace the Kubernetes restore path. Check how patroni--config is looked up and compare that resource with the Service described in the issue. Done means restore handles the Patroni Service correctly instead of treating it as an Endpoint.

Written by the indexing model from the issue text.