The final televised debate between mayoral candidates John R. Connolly and Martin J. Walsh is scheduled for 7 p.m. Tuesday, a week before voters head to the polls. The hourlong debate will take place in the studios of WHDH-TV (Channel 7), with former news anchor R.D. Sahl moderating. The debate is sponsored by the Boston Media Consortium and will air on the channels of all consortium members, making it the most widely aired of the four televised tilts. The stations include WHDH, WGBH-TV (Channel 2), WCVB-TV (Channel 5), NECN, WBUR-FM (90.9), WGBH-FM (89.7), and Bloomberg Radio (1200AM and 94.5FM-HD2).