Depends on the airplane, most small trainers the smaller prop and low
approach speeds the drag from a windmilling prop is hardly noticable
from an idling engine.

On bigger airplanes the larger prop, Bigger engine (develops more HP
even at idle) and the higher approach speed( Drag goes up by the Square
of the speed) the difference between windmilling and idling can be more
noticable (Especially if the idle speed on the engine is set to high)
Brian
CFIIG/ASEL