UI: Add version 1 if KV engine has no version data

[hellobontempo]

Fixes #23463

When a user enables KV in the UI we default to version 2 by passing the version in the options object.

A kv v1 engine is mounted if no version flag is used when enabling kv using the CLI. This is unclear on the READ request because there is no version information in the options key (see below). This PR updates the UI logic so that if no version information exists, the UI assumes it is version 1.

$ vault secrets enable  kv

$ curl   
    --header "X-Vault-Token: root" \
    http://127.0.0.1:8200/v1/sys/mounts | jq
⇒
  "request_id": "fdf6549f-c136-c288-81e5-5e02993ad6c3",
  "lease_id": "",
  "renewable": false,
  "lease_duration": 0,
  "data": {
    "kv-test/": {
      "accessor": "kv_4396c4ae",
      "config": {
        "default_lease_ttl": 0,
        "force_no_cache": false,
        "max_lease_ttl": 0
      },
      "deprecation_status": "supported",
      "description": "",
      "external_entropy_access": false,
      "local": false,
      "options": null, //  <= no version information
      "plugin_version": "",
      "running_plugin_version": "v0.16.1+builtin",
      "running_sha256": "",
      "seal_wrap": false,
      "type": "kv",
      "uuid": "b0306a4d-01da-23dc-c734-925d6e72a579"
    }
 }

[github-actions]

Build Results:
All builds succeeded! ✅

[hashishaw]

Nice! an elegant solution ✨

[github-actions]

CI Results:
All Go tests succeeded! ✅