List contacts

curl --request GET \
  --url https://app.flowella.io/api/v1/contacts \
  --header 'Authorization: Bearer <token>'

{
  "items": [
    {
      "id": "<string>",
      "phone": "<string>",
      "isOptedOut": true,
      "createdAt": "2023-11-07T05:31:56Z",
      "updatedAt": "2023-11-07T05:31:56Z",
      "waId": "<string>",
      "name": "<string>",
      "email": "<string>"
    }
  ],
  "nextCursor": "<string>"
}