Backport of Stop referring non existent vault.file attribute into release/1.6.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #23946 to be assessed for backporting due to the inclusion of the label backport/1.6.x.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
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The person who merged in the original PR is:
@schmichael
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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The documentation is referring to a file attribute that does not exist on the vault block.

This PR changes those references to mention the disable_file attribute instead.

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Overview of commits

• cdaf45d

[hashicorp-cla-app]

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[hashicorp-cla-app]

Thank you for your submission! We require that all contributors sign our Contributor License Agreement ("CLA") before we can accept the contribution. Read and sign the agreement

Learn more about why HashiCorp requires a CLA and what the CLA includes

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[schmichael]

Whoops. I went too far back. Closing this one.