NEW YORK — Manhattan District Attorney Cy Vance Jr. has convened a grand jury that is expected to consider whether to charge Donald Trump and his business executives with crimes as part of a long-running investigation into alleged financial fraud at the former president’s namesake company, according to a report Tuesday. The grand jury was impaneled recently and is expected to consider evidence three days a week for as long as six months, sources familiar with the matter told The Washington Post. Grand jury proceedings are confidential, and it’s unclear if Vance plans to bring charges against T…