Clean up ContractFunctionResult construction HACK in TransactionRecord.fromProtobuf

`TransactionRecord.fromProtobuf` still carries this marker (`sdk/src/main/java/com/hedera/hashgraph/sdk/TransactionRecord.java:317`):

```java
// HACK: This is a bit bad, any takers to clean this up
var contractFunctionResult = transactionRecord.hasContractCallResult()
? new ContractFunctionResult(transactionRecord.getContractCallResult())
: transactionRecord.hasContractCreateResult()
? new ContractFunctionResult(transactionRecord.getContractCreateResult())
: null;
```

Replace the nested ternary with a small explicit helper (or an if/else chain) that picks the call vs. create result, and drop the HACK comment. No behavior change intended — keep both the contract-call and contract-create paths covered by unit tests.

Start in sdk/src/main/java/com/hedera/hashgraph/sdk/TransactionRecord.java at TransactionRecord.fromProtobuf, where the HACK and nested ternary are located. Check the existing unit tests covering contract-call and contract-create results before making the small construction cleanup. Done means both paths remain covered and the HACK comment is removed without behavior changes.

Written by the indexing model from the issue text.