Unable to parse scientific notation string to decimal when scale is 0

[yjshen]

To Reproduce

fn main() -> Result<()> {
    parse_decimal::<Decimal128Type>("1.234e16", 20, 0).unwrap();
    Ok(())
}

Expected behavior

Parse the string successfully.

Additional context

[tustvold]

label_issue.py automatically added labels {'arrow'} from #5740