A large donor to socialist Claire Valdez, a candidate in a tight Democratic primary for New York's Seventh Congressional District, is a notorious city slumlord who once pleaded guilty to felony fraud charges for not paying immigrant laborers, the Washington Free Beacon can reveal. Valdez, an artist and state assembly member, has a narrow lead in the polls against Brooklyn Borough president Antonio Reynoso and City Council member Julie Won in the primary for the deep blue district. Valdez has