The Cook County State’s Attorney’s Office on Tuesday welcomed its newest four-legged employee: a 2-year-old black Labrador retriever named Hatty.As the office’s first support dog, Hatty will serve as a therapeutic resource to assist young children or those with a mental disability who have experienced sexual trauma.At a swearing-in ceremony at the Leighton Criminal Court Building, Hatty briefly placed her right paw on a book while Cook County State’s Attorney Kimberly M. Foxx administered her oath …