As U.S. President Donald Trump keeps threatening Canada’s sovereignty with his 51st state comments, British Foreign Secretary David Lammy is calling for unity — as the United Kingdom continues to avoid directly pushing back on Trump’s annexation talk.Lammy, who joined other G7 foreign ministers for talks in Quebec’s Charlevoix region this week, stressed that “Canada is a proud, strong, sovereign nation” during a Canadian exclusive interview on CBC’s The House airing Saturday.”And [Canada] will continue to be a sovereign nation. Of that, I have no doubt,” Lammy told host Catherine Cullen.Lammy, who has family in Canada, said he recognizes Canadians’…