Photo courtesy DC Fire/EMS Some scaffolding collapsed under a pair of window washers this morning, causing the D.C. fire department to launch a daring high-angle rescue. It happened about 7:30 a.m. at an 11-story building at 1140 Connecticut Ave. NW. One of the workers was able to climb to safety with the help of co-workers, but the second man was stuck dangling eight floors up, so the fire department lowered a rescuer down to…