VATICAN CITY (Reuters) -A two-and-a-half year corruption trial that exposed infighting and intrigue in the highest echelons of the Vatican closes on Saturday with the key defendant, an Italian cardinal, hoping the court will accept his plea of innocence. Cardinal Angelo Becciu, 75, a one-time Vatican power broker, is charged with embezzlement, abuse of office and trying to induce a witness to give false testimony. Becciu, the most senior Vatican official ever to be charged with financial crimes,