Backup list API returns inconsistent response shape when no backups exist

[Tbaile]

Steps to reproduce

• Register a firewall with the cloud backup service.
• Ensure the account has zero backups stored remotely.
• Call:

  api-cli ns.backup registered-list-backups

• Then create at least one backup and call the same method again.

Expected behavior

values always has the same shape: {"backups": [...]}, whether the list is empty or not.

Actual behavior

When backups exist:

{"values": {"backups": [{"id": "...", "name": "...", "created": ..., "size": ..., "mimetype": "..."}]}}

When no backups exist:

{"values": []}

Callers checking for a backups key (or iterating values.backups) break on the empty case since values is a bare array instead of an object.

Components

ns-api 3.7.1 (ns.backup)
nethsecurity-ui 2.23.2

[Tbaile]

QA: with latest dev image check the issue is not reproducible.

[cotosso]

confirmed:

8.8.0

root@NSEC8-VM:~# api-cli ns.backup registered-list-backups
{"values": []}
root@NSEC8-VM:~# Connection to 192.168.56.104 closed by remote host.
Connection to 192.168.56.104 closed.

8.8.0-DEV
davidem@davidem-Latitude-3440:~$ ssh root@192.168.56.104
Warning: Permanently added '192.168.56.104' (ED25519) to the list of known hosts.
root@192.168.56.104's password: 

NethSecurity 8.8.0-dev.367.20260831085632.0c6f019

 * Documentation: https://docs.nethsecurity.org
 * Network: run "setup" to fix network problems

root@NSEC8-VM:~# api-cli ns.backup registered-list-backups
{"values": {"backups": []}}
root@NSEC8-VM:~# 

Anyway the problem occurs only with a freshly created server on the current my.nethesis.it platform.
If just a single backup is created and then deleted (so the list is empty) the problem doesn't occur anymore also with the old implementation.