Ira Lee Law, an arm of the law at the White House, that is a member of the White House police force, was sworn in yesterday as an attorney at law. Ordinarily one of the more modest members of the force. he has worn the uniform for more than 10 years. Laws, never studied at any law school and passed the Bar on his first attempt. Every spare moment from his duties at the executive mansion was spent in the law offices of his friend Carey Quinn. He had studied there four years when he took the examination last June