Export only "net" NFT ownership change in record

### Problem

If a `CryptoTransferTransactionBody` explicitly transfers an NFT from Alice to Bob, and then Bob to Carol, the record's `TokenTransferList` currently shows both ownership changes; instead of a single change from Alice to Carol.

This can make it a bit more complicated for mirror nodes to ingest the record stream ingestion.

### Solution

Only show the "net" ownership change for an NFT in the record of a single `CryptoTransfer`.

### Alternatives

_No response_

Start by tracing how CryptoTransferTransactionBody produces the record's TokenTransferList, focusing on NFT ownership changes within one CryptoTransfer. Confirm the behavior with an Alice-to-Bob-to-Carol transfer; done means the record contains only the net Alice-to-Carol ownership change.

Written by the indexing model from the issue text.