Utilized privacy usage is lost on omitted nodes

[Shoeboxam]

If a node ends up using less privacy than the upper bound provided to it, this lower usage is stored in the release. But nodes introduced by expansions are typically dropped from the release. So if a mechanism invocation inside of a partitional map actually uses less privacy than its upper bound, the record of the reduced usage is not retained in the release- only its downstream union.

Assuming components always respect the upper bound they are given, this bug can only inflate reported privacy usage.