Backport of Replace all remaining time.ParseDurations with parseutil.ParseDurationSeconds into release/1.14.x

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

Backport

This PR is auto-generated from #21357 to be assessed for backporting due to the inclusion of the label backport/1.14.x.

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

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Vault's duration string format supports a strict superset of options compared to Go's duration string format: https://developer.hashicorp.com/vault/docs/concepts/duration-format

In particular, we support days, e.g. 5d, whereas time.ParseDuration does not.

We use parseutil.ParseDurationSeconds everywhere in the code we can, to support our advertised duration format and to be consistent with ourselves. The majority of our code already uses parseutil.ParseDurationSeconds, but there were a few places I found that time.ParseDuration was still being used as part of poking around, so I thought I'd fix them all at once.

I'm not worried about the fact this change changes a lot of files. ParseDurationSeconds is battle-tested, and there's no valid duration that time.ParseDuration supports that we don't also support.

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Overview of commits

• 3a46ecc

[VioletHynes]

Re-requesting my own review on this so GitHub will nag me every day until I hit approve it. I'll approve and merge when 1.14 is released and it's good to merge into the release branch, but I don't want to merge now as we're nearing the end of the release cycle.