[PhuocOng]

Fixes #4094.

The metrics Service uses the argo-rollouts.namespace helper, but the ServiceMonitor target selector uses .Release.Namespace. When namespaceOverride differs from the release namespace, the monitor cannot select the Service it is meant to scrape.

Use the same namespace helper for spec.namespaceSelector.matchNames. The monitor's own configurable namespace, labels and endpoint port are unchanged. No new values, images or dependencies.

Validation (Helm 4.2.3, chart-testing 3.14.0, kind / Kubernetes 1.35.0):

• Four local structured render cases cover with/without namespaceOverride and with/without a separate monitor namespace. Both override cases fail before the fix; all four pass afterward, including matching Service labels and ports.
• All three existing chart-testing install configurations pass. Repository lint, changelog lint, generated-docs diff and ArtifactHub lint pass.
• With the official ServiceMonitor CRD installed, a live chart install places the monitor in a separate monitoring namespace, selects the overridden workload namespace and exposes a reachable metrics endpoint. This checks resources and endpoint reachability, not a full Prometheus Operator scrape loop.
• Default resources are unchanged apart from chart-version labels.

Upstream Linting and Testing passed on commit d86229fd09153b380a1d6411f22b6fab58d01fb5, including all three install configurations. All seven PR checks passed.

Prepared with GitHub Copilot assistance.

Checklist:

• I have bumped the chart version according to versioning
• I have updated the documentation according to documentation
• I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• I wrote this PR with the help of a LLM but I fully vetted the work before raising this PR for review
• Any new values are backwards compatible and/or have sensible default.
• I have signed off all my commits as required by DCO.
• I have created a separate pull request for each chart according to pull requests
• My build is green (troubleshooting builds).

[tico24]

#4104 also uses 2.43.3 and is set to auto-merge, so could you bump this to 2.43.4?