[kube-state-metrics] fix fullname duplication with nameOverride

[firasmosbehi]

Summary

This PR fixes fullname generation for kube-state-metrics when nameOverride already includes the release name, addressing #6510.

Problem

With Release.Name=ksm-non-pods and nameOverride=ksm-non-pods-foo, rendered object names become double-prefixed (ksm-non-pods-ksm-non-pods-foo).

Root cause

The fullname helper only handled the case where release name contains chart/name. It did not handle the inverse case where nameOverride already contains release name.

Fix

Updated kube-state-metrics.fullname helper logic to add an inverse containment branch:

• keep existing behavior if release name already contains chart/name
• if nameOverride contains release name, use nameOverride as fullname
• otherwise keep concatenation behavior

Also bumped chart version from 7.2.0 to 7.2.1.

Validation

• helm lint charts/kube-state-metrics
• helm template ksm-non-pods charts/kube-state-metrics --set nameOverride=ksm-non-pods-foo
• Verified rendered names are ksm-non-pods-foo and no ksm-non-pods-ksm-non-pods-foo names are produced.

Compatibility

Existing default naming behavior is preserved unless nameOverride already embeds the release name.