(The Center Square) – Elon Musk, the tech billionaire who founded Tesla and SpaceX, made one simple request at former President Donald Trump’s campaign rally on Saturday. Register to vote – and then actually cast a ballot on Election Day. “President Trump must win to preserve the Constitution,” Musk said to the crowd gathered in Butler, about 45 minutes north of Pittsburgh. “He must win to preserve democracy and America. This is a must-win situation. A must win.” Musk, donning a black “Make America Great Again” hat, bounced onto the stage with a smile after Trump, midway through his speech, in…