🌱 Update md link check for release-1.9

[cahillsf]

What this PR does / why we need it:
following https://github.com/kubernetes-sigs/cluster-api/tree/main/docs/release/role-handbooks/ci-signal#setup-jobs-and-dashboards-for-a-new-release-branch

update the link check

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[k8s-ci-robot]

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