Send sticker

curl -X POST "https://api.wazapin.id/v1/messages" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "channel_id": "wzp_abc123",
    "to": "6281234567890",
    "type": "sticker",
    "content": {
      "sticker_url": "https://cdn.example.com/stickers/thanks.webp"
    }
  }'