Backport

This PR is auto-generated from #29122 to be assessed for backporting due to the inclusion of the label backport/1.18.x.

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

Description

The static x509 certificate is expiring Jan 6 2025 and is now causing test failures within the diagnose test cases.

Instead of just reissuing the certificate and having to deal with this in the future, codify the generation of certificates and test cases that we want to validate so the certificates will never expire again.

For time reasons, I haven't fixed all the test cases, mainly the ones that were causing issues for now.

TODO only if you're a HashiCorp employee

• Backport Labels: If this fix needs to be backported, use the appropriate backport/ label that matches the desired release branch. Note that in the CE repo, the latest release branch will look like backport/x.x.x, but older release branches will be backport/ent/x.x.x+ent.
  • LTS: If this fixes a critical security vulnerability or severity 1 bug, it will also need to be backported to the current LTS versions of Vault. To ensure this, use all available enterprise labels.
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  of a public function, even if that change is in a CE file, double check that
  applying the patch for this PR to the ENT repo and running tests doesn't
  break any tests. Sometimes ENT only tests rely on public functions in CE
  files.
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