[kube-state-metrics] align metricAnnotationsAllowlist naming

[firasmosbehi]

Summary

This PR adds the normalized metricAnnotationsAllowlist values key to kube-state-metrics while preserving backward compatibility with the existing metricAnnotationsAllowList key, addressing #5651.

Problem

The chart uses metricAnnotationsAllowList while related options use the Allowlist casing convention. This is inconsistent and causes confusion.

Root cause

The value and template wiring were implemented only with the older AllowList casing.

Fix

• Added metricAnnotationsAllowlist to values.yaml.
• Kept metricAnnotationsAllowList as a deprecated compatibility alias.
• Updated deployment args rendering to prefer metricAnnotationsAllowlist and fall back to metricAnnotationsAllowList.
• Bumped chart version from 7.2.0 to 7.2.1.

Validation

• helm lint charts/kube-state-metrics
• helm template test charts/kube-state-metrics --set-string 'metricAnnotationsAllowlist[0]=pods=[kubernetes.io/team]'
• helm template test charts/kube-state-metrics --set-string 'metricAnnotationsAllowList[0]=pods=[legacy/key]'
• Verified both render the expected --metric-annotations-allowlist=... argument.

Compatibility

Backward compatible by design: existing users of metricAnnotationsAllowList continue to work.