WASHINGTON — As President Joe Biden visited five cities in a multiday trip last week, former President Donald Trump was hardly seen in public, spending most of his time in South Florida. Trump has held just a single public campaign event since he locked up the Republican presidential nomination on March 12: a rally in Ohio funded not by his campaign but by backers of a Senate candidate whom he had endorsed. The events page on his campaign website has had nothing listed.Biden, meanwhile, has…