curl --location '/api/public/landings/launch//unsubscribe' \
--header 'Accept-Language;' \
--header 'Content-Type: application/json' \
--data '{
"source": "vk_app",
"channel_public_id": "a1b2c3d4",
"platform_payload": "query_id=...&user=...&auth_date=...&hash=..."
}'{
"state": "subscribed"
}