Date type transformed to uint16 when export to Dataframe

**Describe the issue**
When a query retuns Date type and it is exported to Dataframe or Arrow, it will be transformed to 

**How to reproduce**
```
res = chdb.query('SELECT toDate(now())', 'Dataframe')
res
>>>toDate(now())
>>>0          19585

res = chdb.query('SELECT toDate32(now())', 'Dataframe')
res
>>>toDate32(now())
>>>0      2023-08-16
```
