By Andrew MacAskill and Matthew Childs LONDON/DOVER (Reuters) -Britain’s first scheduled flight taking asylum seekers to Rwanda was set to depart on Tuesday, with the government warning that anyone who avoided it through last-minute legal challenges would be put on a later plane despite an outcry from critics. Britain has struck a 120-million-pound ($148 million) deal with Rwanda to send some migrants, who had arrived by crossing the English Channel in small boats from Europe, to live in the East African country. The plan, which the government says will stem the flow of dangerous cross-Channel…