Choose which fields get flattened by complexType

Say we have the following event structure:

```json
{
"...",
"auditFields": {
"a": "b",
"c": "d"
},
"results": [
{
"name": "result1",
"value": 33.2
},
{
"name": "result2",
"value": 45.6
}
]
}
```

We want to create the following columns:

```
results.name
results.value
auditFields
```

At the moment I don't think that's possible as auditFields will be flattened into:

```
audiFields.a
auditFields.c
```

By this line of code - https://github.com/apache/pinot/blob/master/pinot-segment-local/src/main/java/org/apache/pinot/segment/local/recordtransformer/ComplexTypeTransformer.java#L176

Can we make the columns that get flattened configurable, like the fields to unnest can be configured?