NEW YORK — For federal prosecutors, Sam Bankman-Fried could be the gift that keeps on giving.After the November collapse of FTX, the cryptocurrency exchange he founded in 2019, Bankman-Fried unexpectedly gave a series of interviews intended to present his version of events. He was indicted in December and charged with perpetrating one of the biggest frauds in U.S. history — and he’s still talking, either in person or on the internet.The atypical chattiness for a criminal defendant is likely causing …