Converting base field elements to extension filed elements in codegen

For auxiliary constraints using main trace columns we check if the trace_segment != 0 and convert base field to extension field elements:

```
if self.trace_segment() == 0 && self.trace_segment() != trace_segment {
format!("E::from({frame}_{row_offset})")
} else {
format!("{frame}_{row_offset}")
}
```

This requires us to pass `trace_segment` to the `to_string()` method. Ideally we should infer this using just `elem_type`.

_Originally proposed by @grjte in https://github.com/0xPolygonMiden/air-script/pull/169#discussion_r1115772148_