PathListingWidget : Avoid unnecessary `Path::copy()` calls
PathListingWidget : Avoid unnecessary `Path::copy()` calls

This knocks around 40% off a Moana update benchmark.

GafferHQ/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer