WASHINGTON — President-elect Joe Biden has selected Merrick Garland, a federal appeals court judge who in 2016 was snubbed by Republicans for a seat on the Supreme Court, as his attorney general, two people familiar with the selection process said Wednesday.Biden is expected to announce Garland’s appointment on Thursday, along with other senior leaders of the department, including former homeland security adviser Lisa Monaco as deputy attorney general and former Justice Department civil rights chief Vanita Gupta as …