The Trump administration’s mass-deportation offensive expanded into Los Angeles Saturday with pre-dawn roundups, part of a West Coast operation expected to run seven days a week, sources told The Post.Immigration agents avoided sections of the city suffering the most damage from the devastating wildfires burning through parts of Southern California, the sources noted.The effort was part of the major crackdown in large cities across America that President Trump promised on the campaign trail and has focused on booting criminal migrants, sources added.