Define isa_vertical_space

src/Remapping/distributed_remapping.jl

@@ -1003,6 +1003,7 @@ function interpolate!(
     if only_one_field
         fields = [fields]
     end
+    isa_vertical_space = remapper.space isa Spaces.FiniteDifferenceSpace
 
     if !isnothing(dest)
         # !isnothing(dest) means that this is the root process, in this case, the size have