NEW YORK — FTX founder Sam Bankman-Fried left a federal courtroom in handcuffs Friday when a judge revoked his bail after concluding that the fallen cryptocurrency wiz had repeatedly tried to influence witnesses against him. Bankman-Fried drooped his head as Judge Lewis A. Kaplan explained at length why he believed the California man had repeatedly pushed the boundaries of his $250 million bail package to a point that Kaplan could no longer ensure the protection of the community, including prosecutors’ witnesses, unless the 31-year-old was behind bars. After the hearing ended, Bankman-Fried took off his suit jacket and tie and turned his watch and other personal belongings over to his lawyers.