Backport of auth/ldap: Add username to alias.metadata.name into release/1.9.x

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

Backport

This PR is auto-generated from #13669 to be assessed for backporting due to the inclusion of the label backport/1.9.x.

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

---

A change introduced in #11000 introduced a subtle change to entity aliases when upndomain is configured. When using upndomain, the name value in the alias now contains the value stored in upndomain:

{
  "data": {
    "aliases": [
      {
        ...
        "name": "bob@corp.example.net"
      }
    ],
  },
}

This has caused issues in 1.9.x where users are using templated policies and now the UPN domain is being appended. I've added alias.metadata.name which contains the raw username without UPN domain.

"aliases": [
  {
    "canonical_id": "c05d6c0a-8d0b-f10b-ab9a-26bb09abf821",
    "creation_time": "2022-01-14T22:00:51.8852898Z",
    "custom_metadata": null,
    "id": "290f51a7-14d9-8488-c344-20ce7b159fd5",
    "last_update_time": "2022-01-14T22:00:51.8852898Z",
    "local": false,
    "merged_from_canonical_ids": null,
    "metadata": {
      "name": "bob"
    },
    "mount_accessor": "auth_ldap_6e553280",
    "mount_path": "auth/ldap/",
    "mount_type": "ldap",
    "name": "bob@corp.example.net"
  }