LONDON — As U.S. President Donald Trump re-imposed harsh economic sanctions on Iran last month, hackers scrambled to break into personal emails of American officials tasked with enforcing them, The Associated Press has found — another sign of how deeply cyberespionage is embedded into the fabric of U.S.-Iranian relations. The AP drew on data gathered by the London-based cybersecurity group Certfa to track how a hacking group often nicknamed Charming Kitten spent the past month trying to break into the private emails of more than a dozen U.S.