bug: ArrowSchemaConverter can't handle unsigned datatypes from arrow

[sundy-li]

error throws for unsigned types

  _ => Err(Error::new(
                ErrorKind::DataInvalid,
                format!("Unsupported Arrow data type: {p}"),
            )),

cc @Xuanwo

[Xuanwo]

Thank you for the report. I will take a look.

[liurenjie1024]

Iceberg has no built in support for unsigned data types, and I think we could handle this by storing signed value and do byte to byte conversion in read time.