[chore] fix markdown link closing in k8s_metrics notes

[emdneto]

I'm not sure if it needs a changelog, but let me know if that is the case.

Changes

Please provide a brief description of the changes here.

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Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• [] schema-next.yaml updated with changes to existing conventions.

[emdneto]

I think CI error will be solved by #1825

[ChrsMark]

Thank's!