fetch_secrets does not return server entries

I am using the latest module version 1.2.1 in AWX.

```
secrets:
- secret_id: 3896b201-dd79-47c8-bf19-7c95979f008c
```

```
- name: Get SSH Key from DVLS
hosts: localhost
gather_facts: false
tasks:
- name: Fetch secrets
devolutions.dvls.fetch_secrets:
server_base_url: "https://my-dps-server/dps"
app_key: "{{ ansible_user }}"
app_secret: "{{ ansible_password }}"
vault_id: "00000000-0000-0000-0000-000000000000"
secrets: "{{ secrets }}"
register: value

- name: Dump secrets
debug:
msg: "{{ value }}"
```

The secret id specified is an SSH Server entry from which I need to retrieve the SSH private key. But it returns nothing.

Output:
```
msg:
3896b201-dd79-47c8-bf19-7c95979f008c: {}
failed: false
changed: false
_ansible_verbose_always: true
_ansible_no_log: false
changed: false
```

When I fetch all secrets from DVLS and dump them, it seems that only credential and api key entries are returned.