Get attachment metadata

curl --request GET \
  --url https://api.relayapp.im/v1/attachments/{attachmentId} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "filename": "<string>",
  "content_type": "<string>",
  "size_bytes": 123,
  "status": "pending",
  "created_at": "2023-11-07T05:31:56Z",
  "download_url": "<string>",
  "duration_ms": 1,
  "width": 2,
  "height": 2
}

{
  "error": {
    "status": 123,
    "code": 123,
    "message": "<string>",
    "doc_url": "<string>",
    "retry_after": 123
  },
  "success": true,
  "trace_id": "<string>"
}

{
  "error": {
    "status": 123,
    "code": 123,
    "message": "<string>",
    "doc_url": "<string>",
    "retry_after": 123
  },
  "success": true,
  "trace_id": "<string>"
}

{
  "error": {
    "status": 123,
    "code": 123,
    "message": "<string>",
    "doc_url": "<string>",
    "retry_after": 123
  },
  "success": true,
  "trace_id": "<string>"
}