LONDON — Britain’s center-left government is taking direct inspiration from Denmark’s hardline treatment of migrants — and leaving some of its own MPs feeling queasy. Home Secretary Shabana Mahmood will face down assembled critics from refugee charities and beyond in a speech in London Thursday morning, making what she calls the “progressive,” Labour case for overhauling Britain’s asylum system. Mahmood is fresh from a fact-finding mission to Copenhagen — and wants to import many of the