There are cases where the default input passes of color+albedo do not yield useful results
and while this was possible to change that for final frame rendering (in the layer settings),
viewport denoising always used a fixed color+albedo. This adds an option to change the
input passes for viewport denoising too, so that one can use it in scenes that otherwise
wouldn't work well with it.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D10404