Facebook CEO Mark Zuckerberg speaks during a live-streamed virtual and augmented reality conference to announce the rebrand of Facebook as Meta, in this screen grab taken from a video released October 28, 2021.Facebook | via ReutersMark Zuckerberg's ambitious plan to build his own cryptocurrency is falling apart, amid growing pressure from regulators.The Diem Association, which oversees development of the Diem digital currency, is considering a sale of its assets, in order to return capital to its investors, according to…