Arcane: Container-registry credential exfiltration via URL repoint + test to attacker host

Arcane is an interface for managing Docker containers, images, networks, and volumes. Prior to 2.5.0, UpdateRegistry and TestRegistry in backend/api/services/container_registry_service.go allow the registry URL to change while preserving the stored encrypted token. When a holder of registries:update and registries:test repoints a generic registry URL without supplying a replacement token, TestRegistry decrypts the preserved token and RegistryLogin sends it to the attacker-controlled host because normalizeRegistryServerAddressInternal does not restrict the destination. This exposes the stored container-registry PAT or password and can enable image access or tampering. This issue is fixed in version 2.5.0.