WASHINGTON — Ivanka Trump, the president’s daughter and a powerful White House aide, is not preserving all of her official email communications as required by federal law, the chairman of the House Oversight and Reform Committee said on Thursday. Rep. Elijah Cummings, D-Md., said in a letter that Trump’s lawyer, Abbe Lowell, informed the committee late last year that Trump doesn’t preserve official emails she receives in her personal account if she doesn’t respond to them.