Legal ethics watchdogs in the District of Columbia and Georgia have dismissed complaints against the lawyer Stefan C. Passantino over allegations that he pressured a former client, Cassidy Hutchinson, to remain loyal and protect former President Donald J. Trump by saying little to Congress about his conduct in the lead-up to the Jan. 6, 2021, Capitol attack.Ms. Hutchinson declined to cooperate with the inquiries by repeating to investigators the allegations she had made to Congress about Mr. Passantino, whom she replaced as her lawyer before testifying publicly to the House Jan. 6…