Remove HVD API link (#1149)

## Description

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:ticket: [SPE-1333]

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necessary relevant links -->

- Remove HVD API link pending updates

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### Requested review scope:

- [x] Content touched by the PR _only_ (typos, clarifications, tips)
- [ ] Code test (command and code block changes)
- [ ] Flow and language near changes (new/rearranged steps)
- [ ] Review everything (rewrites, major changes)

### Review urgency:

- [ ] ASAP (bug fixes, broken content, imminent releases)
- [ ] 3 days (small changes, easy reviews)
- [ ] 1 week (default)
- [x] Best effort (very non-urgent)

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## All updates:

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I have:

- [ ] Verified that all status checks have passed
- [x] Verified that preview environment has successfully deployed
- [x] Verified appropriate `label` applied (`hcp` + `product name`)
- [x] Added all required reviewers (code owners and external)


[SPE-1234]:
https://hashicorp.atlassian.net/browse/SPE-1234?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ
[SPE-1333]:
https://hashicorp.atlassian.net/browse/SPE-1333?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: jonathanfrappier

content/hcp-docs/data/docs-nav-data.json

@@ -762,10 +762,6 @@
         "title": "Secrets inventory reporting<sup>Beta</sup>",
         "path": "vault/secrets-inventory"
       },
-      {
-        "title": "HCP Vault API",
-        "href": "/hcp/api-docs/vault"
-      },
       {
         "title": "Additional resources",
         "routes": [