How to set the no_proxy params in Alertmanager?

Question

Problem

I'm currently deploying the kube-prom-stack HELM chart (from the prometheus-community), setting-up Alertmanager, and got an issue while setting no_proxy parameter inside a receiver conf. The issue is that Alertmanager isn't deployed while setting no_proxy, no pods and neither Alertmanager-operated service.

Configuration

Here is my Alertmanager conf from HELM values.yaml:

## Configuration for alertmanager
## ref: https://prometheus.io/docs/alerting/alertmanager/
##
alertmanager:
  ## Alertmanager configuration directives
  ## ref: https://prometheus.io/docs/alerting/configuration/#configuration-file
  ##      https://prometheus.io/webtools/alerting/routing-tree-editor/
  ##
  config:
    route:
      receiver: "receiver_A"
      routes:
      - receiver: "receiver_A"
        match:
          severity: "critical"
    receivers:
      - name: receiver_A
        slack_configs:
            # Whether to notify about resolved alerts.
          - send_resolved: true
            icon_url: https://avatars3.githubusercontent.com/u/3380462
            color: '{{ template "slack.color" . }}'
            title: '{{ template "slack.title" . }}'
            text: '{{ template "slack.text" . }}'
            # The Slack webhook URL. Either api_url or api_url_file should be set.
            # Defaults to global settings if none are set here.
            api_url: <URL_>
            # The HTTP client's configuration.
            http_config:
              proxy_url: '<HTTP_PROXY>'
              no_proxy: '<any_values>'

Context

• Kubernetes: 1.28
• kube-prom-stack: 55.11.0

What I try ?

Following the Alertmanager documentation about the http_config and no_proxy param, without success.

Expected behaviour

I expected the Alertmanager component being deployed without with no_proxy setter. Is someone able to reproduce the problem ?