List contacts

curl -X GET "https://api.live.paisr.tech/v2/wallets/{wallet_id}/contacts" \
  -H "Authorization: Bearer <access_token>" \
  -H "User-Agent: MyApp/1.0" \
  -H "Content-Type: application/json"

{
  "success": true,
  "data": {
    "contacts": [
      {
        "id": "fav_123456",
        "full_name": "Jane Smith",
        "nickname": "Jane",
        "cashtag": "janesmith",
        "avatar": "https://gravatar.com/avatars/uhofasobobao",
        "created_at": "2024-01-15T10:30:00Z"
      }
    ]
  }
}