By Ben Aris in Berlin Two small children, Sofia, a girl, and Daniel, a boy, were shown climbing into a plane that was about to take a mix of cybercriminals, spies and an assassin back to Russia as part of a massive prisoner swap on August 1. They were the children of a sleeper agent couple arrested in Slovenia and released again as part of the deal. But the kids only found out they were Russian after the plane took off. The children’s parents seemed to be perfectly normal. Artem and Anna Dultsev were an Argentinian couple that have been living in Ljubljana, the capital of EU member Slovenia, s…