List Portfolio Users

curl --request GET \
  --url https://api.prime.coinbase.com/v1/portfolios/{portfolio_id}/users

{
  "users": [
    {
      "id": "<string>",
      "name": "<string>",
      "email": "<string>",
      "portfolio_id": "<string>",
      "entity_id": "<string>",
      "role": "USER_ROLE_UNKNOWN"
    }
  ],
  "pagination": {
    "next_cursor": "<string>",
    "sort_direction": "DESC",
    "has_next": true
  }
}