Backport of ignore leading slash in kv get command into release/1.11.x

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

Backport

This PR is auto-generated from #16443 to be assessed for backporting due to the inclusion of the label backport/1.11.x.

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

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Handling of leading slashes was not consistent in the vault kv get command. This can be fixed by simply ignoring the leading slash of the requested path. The following will all successfully fetch a secret at path secret/foo:

vault kv get /secret/foo

vault kv get secret/foo

vault kv get -mount=secret /foo

vault kv get -mount=secret foo

Fixes #16238

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Overview of commits

• dc5133f