WASHINGTON — A federal judge has ruled that former Vice President Mike Pence will have to testify before a grand jury in the Justice Department’s investigation into efforts by former President Donald Trump and his allies to overturn the results of the 2020 election.That’s according to two people familiar with the ruling, who spoke on condition of anonymity because it remains under seal.The people said, however, that Pence would not have to answer questions about his actions on Jan. 6, 2021, when a mob of …