discovery(scaleway): instances without private IPs are not added to the target lists

[Heyoxe]

What did you do?

We are using Scaleway instances with routed IPs. Due to how routed IPs work, those instances have no private IPs.
The documentation says that the Scaleway SD uses the public IPv4 address by default. We have relabelled the instances to use their public IPv4 instead.

What did you expect to see?

We expect our instances with routed IPs to show up in Scaleway's service discovery with their public IP as addresses.

What did you see instead? Under which circumstances?

Instances with routed IPs (and therefor no private IPs) are not listed at all.

System information

Linux 5.15.150.1-microsoft-standard-WSL2 x86_64

Prometheus version

prometheus, version 2.51.2 (branch: main, revision: b938bbc11169dc224c103bec32a55daad0f3f34e)
  build user:       root@desktop
  build date:       20240416-17:19:29
  go version:       go1.22.0
  platform:         linux/amd64
  tags:             netgo,builtinassets,stringlabels

Prometheus configuration file

global:
  scrape_interval: 15s
  evaluation_interval: 15s

scrape_configs:
  - job_name: scaleway
    scaleway_sd_configs:
      - role: instance
        project_id: 11111111-1111-1111-1111-111111111111
        access_key: SCWXXXXXXXXXXXXXXXXX
        secret_key: 11111111-1111-1111-1111-111111111111

    relabel_configs:
      - source_labels: [ __meta_scaleway_instance_public_ipv4 ]
        replacement: "${1}:9090"
        target_label: __address__

Alertmanager version

No response

Alertmanager configuration file

No response

Logs

No response