Backport of CE changes for plugin download into release/1.20.x

[hc-github-team-secure-vault-core]

Backport

This PR is auto-generated from #30927 to be assessed for backporting due to the inclusion of the label backport/1.20.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:
@lursu
This person should resolve the merge-conflict(s) by either:

• Manually completing the cherry picks into this branch
• Creating a new branch and manually cherry-picking all commits being backported

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

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

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Description

This PR follows the How To Merge PRs Containing CE + Ent Changes guide to generate the subset of CE changes from https://github.com/hashicorp/vault-enterprise/pull/8193.

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.
• ENT Breakage: If this PR either 1) removes a public function OR 2) changes the signature
  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.
• Jira: If this change has an associated Jira, it's referenced either
  in the PR description, commit message, or branch name.
• RFC: If this change has an associated RFC, please link it in the description.
• ENT PR: If this change has an associated ENT PR, please link it in the
  description. Also, make sure the changelog is in this PR, not in your ENT PR.

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Overview of commits

• 146c032

[hashicorp-cla-app]

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---

1 out of 2 committers have signed the CLA.

• helenfufu
• temp

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[github-actions]

CI Results:
All Go tests succeeded! ✅

[maithyton]

LGTM

[github-actions]

Build Results:
All builds succeeded! ✅