Remove 1 or 2 remaining places where relatedObjects is called in completeOrder

Remove 1 or 2 remaining places where relatedObjects is called in completeOrder

If we remove this & the other place we no longer need to call loadRelatedObjects before this
function and only message related places call it

In this case the lines can go as

1) trxn_id should always be used if provided. Casting to isoDate has not been required for a few
years as the DAO now handles