By Jorgelina do Rosario and Andrea Shalal BUENOS AIRES/WASHINGTON (Reuters) – Senior U.S. officials from the National Security Council and the Treasury will visit Argentina later this week, an important sign of support just days after libertarian President Javier Milei took office, four people familiar with the matter told Reuters. Deputy National Security Adviser Mike Pyle will be in Buenos Aires on Wednesday, according to three sources who asked not to be named because the travel agenda is still not public. The U.S. Treasury’s top international official, Jay Shambaugh, is set to head to Buen…