auth/ldap: Add username to alias.metadata.name

[jasonodonnell]

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"
  }