ShipmentInsertionCalculator - JobInsertionContext does not clear RelatedActivityContext

In a delivery loop
calculator set **relatedActivityContext** (pickup information) and **activityContext** (delivery information)

in the next pickup loop, before delivery loop
we have situation that insertionContext has **activityContext** (new pickup information) and **relatedActivityContext** (previous pickup information)

So in any constraint if we use relatedActivityContext field we have wrong information there. I think null is expected when you check pickupShipment activity.

Is is a bug or there is any reason why we need previous pickup information in the **relatedActivityContext** field?

Start by tracing ShipmentInsertionCalculator and JobInsertionContext through the delivery and pickup loops. Verify whether relatedActivityContext should be cleared before processing a pickup, and confirm the expected value when pickupShipment constraints inspect it; done means the context no longer exposes stale pickup information.

Written by the indexing model from the issue text.