Backport of nds: add validation for tls_skip_verify into release/1.5.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #18333 to be assessed for backporting due to the inclusion of the label backport/1.5.x.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
you will see a blank no-op commit below. If at least one commit succeeded, you
will see the cherry-picked commits up to, not including, the commit where
the merge conflict occurred.

The person who merged in the original PR is:
@lgfa29
This person should manually cherry-pick the original PR into a new backport PR,
and close this one when the manual backport PR is merged in.

merge conflict error: POST https://api.github.com/repos/hashicorp/nomad/merges: 409 Merge conflict []

The below text is copied from the body of the original PR.

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TLSSkipVerify is ignored for Nomad service checks.

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Overview of commits

• da830b1

[hashicorp-cla]

All committers have signed the CLA.