Update desk review workbook to pull comps using doc numbers

[jeancochrane]

We currently save doc numbers as well as PINs for each comp that a card has, but the desk review workbooks that we output in the export pipeline stage still infer sale dates based on the most recent sale for a comp PIN. This imputation process usually finds the correct value, but it's not guaranteed to be correct. To be safe, we should update the export stage to assign comps using comp doc numbers instead of using the most recent sale for a comp PIN.