WASHINGTON — White House officials sought to “lock down” records of a phone call in which President Donald Trump urged his Ukrainian counterpart to investigate Democratic rival Joe Biden, according to a secret whistleblower complaint made public Thursday. The document was released ahead of scheduled testimony from Joseph Maguire, the acting director of national intelligence. House Democrats who are now mulling Trump’s impeachment are hoping Maguire will explain why he withheld the intelligence community whistleblower’s complaint from Congress for weeks.