Backport of UI: Remove leading slash from kv version 2 secret path into release/1.15.x

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

Backport

This PR is auto-generated from #25874 to be assessed for backporting due to the inclusion of the label backport/1.15.x.

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

---

Typically we avoid sanitizing in the UI to minimize data manipulation, however we decided to strip secret paths of the leading slash to copy CLI functionality.

 vault kv put -mount=kv /my-secret foo=my-long-passcode
== Secret Path ==
kv/data/my-secret

======= Metadata =======
Key                Value
---                -----
created_time       2024-03-11T16:59:42.502882Z
custom_metadata    <nil>
deletion_time      n/a
destroyed          false
version            1
⇒ vault kv put -mount=kv //my-secret foo=my-long-passcode
== Secret Path ==
kv/data/my-secret

======= Metadata =======
Key                Value
---                -----
created_time       2024-03-11T17:00:01.047652Z
custom_metadata    <nil>
deletion_time      n/a
destroyed          false
version            2


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<details>
<summary> Overview of commits </summary>

  - 0d71b2a3ddd9e5651d861f36091f3e084cd21c96 

</details>

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