Enable Duckdb index on nested texts
E.g. for dialog datasets with features
```python
Features({
    "conversations": [{"from": Value("string"), "value": Value("string")}]
})
```

like https://huggingface.co/datasets/LDJnr/Puffin
Enable Duckdb index on nested texts: E.g. for dialog datasets with features
```python
Features({
    "conversations": [{"from": Value("string"), "value": Value("string")}]
})
```

like https://huggingface.co/datasets/LDJnr/Puffin