[CONTINT-4643] Add an option to configure KSM custom resource metrics collection

[L3n41c]

What does this PR do?

Add an datadog agent parameter to configure custom resources metrics collection introduced in DataDog/datadog-agent#31715.

Motivation

Additional Notes

This the datadog-operator equivalent of DataDog/helm-charts#1883.

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: v7.63.0 (if kubernetes-state-core is running on cluster checks runners)
• Cluster Agent: v7.63.0 (otherwise)

Describe your test plan

Create a DatadogAgent CR with the following piece of KSM configuration:

spec:
  features:
    kubeStateMetricsCore:
      collectCrMetrics:
      - groupVersionKind:
          group: datadoghq.com
          kind: DatadogAgent
          version: v2alpha1
        metrics:
        - each:
            gauge:
              path:
              - status
              - agent
              - upToDate
            type: gauge
          help: Number of up-to-date agents
          name: uptodateagents

And validate that the corresponding custom resource metric is properly emitted:

$ kubectl exec pod/dda-with-operator-cluster-agent-79988798b9-9t7f7 -c cluster-agent -- env -u DD_LOG_LEVEL agent check -r kubernetes_state_core --table
[…]
  kubernetes_state_customresource.uptodateagents             gauge  1755816713  1             kube_cluster_name:lenaic-kind, customresource_group:datadoghq.com, customresource_kind:DatadogAgent, customresource_version:v2alpha1, orch_cluster_id:596fb22b-2124-4b0a-91a9-dca1b37078f8

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 39.10%. Comparing base (977f372) to head (1188d65).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...agent/feature/kubernetesstatecore/indent_writer.go	76.00%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1927      +/-   ##
==========================================
+ Coverage   38.97%   39.10%   +0.13%     
==========================================
  Files         253      254       +1     
  Lines       26208    26275      +67     
==========================================
+ Hits        10214    10275      +61     
- Misses      15386    15390       +4     
- Partials      608      610       +2     

Flag	Coverage Δ
unittests	39.10% <92.00%> (+0.13%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...adogagent/feature/kubernetesstatecore/configmap.go	96.20% <100.00%> (+0.96%)	⬆️
...atadogagent/feature/kubernetesstatecore/feature.go	71.52% <100.00%> (+0.40%)	⬆️
...r/datadogagent/feature/kubernetesstatecore/rbac.go	100.00% <100.00%> (ø)
...agent/feature/kubernetesstatecore/indent_writer.go	76.00% <76.00%> (ø)

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[L3n41c]

/merge

[dd-devflow-routing-codex]

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2025-10-13 12:03:09 UTC ℹ️ Start processing command /merge

---

2025-10-13 12:03:15 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 0s (p90).

---

2025-10-13 14:03:41 UTC ❌ MergeQueue: The build pipeline has timeout

The merge request has been interrupted because the build 79133870 took longer than expected. The current limit for the base branch 'main' is 120 minutes.

[L3n41c]

/merge

[dd-devflow-routing-codex]

View all feedbacks in Devflow UI.

2025-10-14 09:39:17 UTC ℹ️ Start processing command /merge

---

2025-10-14 09:39:23 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 0s (p90).

---

2025-10-14 11:39:42 UTC ❌ MergeQueue: The build pipeline has timeout

The merge request has been interrupted because the build 79210032 took longer than expected. The current limit for the base branch 'main' is 120 minutes.