Don't use skimValue.BlendVariable outside of the ImpedanceRoster.GetValue for parcel-parcel

[mabcal]

Look for all cases where .BlendVariable is used to set a distance value (outside of the blending process itself), and change it use a GetValue call for "distance" instead, to avoid further potential bugs. Most or all of these cases are in PathTypeModel for auto, bike and walk.