Decimal128 to Decimal256 Overflows

[tustvold]

Describe the bug

#[test]
    fn test_cast_decimal128_to_decimal256_negative() {
        let input_type = DataType::Decimal128(10, 3);
        let output_type = DataType::Decimal256(10, 5);
        assert!(can_cast_types(&input_type, &output_type));
        let array = vec![Some(i128::MAX), Some(i128::MIN)];
        let input_decimal_array = create_decimal_array(array, 10, 3).unwrap();
        let array = Arc::new(input_decimal_array) as ArrayRef;

        let hundred = i256::from_i128(100);
        generate_cast_test_case!(
            &array,
            Decimal256Array,
            &output_type,
            vec![
                Some(i256::from_i128(i128::MAX).mul_wrapping(hundred)),
                Some(i256::from_i128(i128::MIN).mul_wrapping(hundred))
            ]
        );
    }

Fails with

thread 'cast::tests::test_cast_decimal128_to_decimal256_negative' panicked at 'assertion failed: `(left == right)`
  left: `0`,
 right: `17014118346046923173168730371588410572700`', arrow-cast/src/cast.rs:7251:9

The issue is that it is not performing the scaling operation in the destination type

let iter = array.iter().map(|v| {
    v.and_then(|v| v.mul_checked(mul).ok().map(i256::from_i128))
});
let casted_array = unsafe {
    PrimitiveArray::<Decimal256Type>::from_trusted_len_iter(iter)
};
casted_array
    .with_precision_and_scale(*output_precision, *output_scale)
    .map(|a| Arc::new(a) as ArrayRef)

To Reproduce

Expected behavior

Additional context

[alamb]

label_issue.py automatically added labels {'arrow'} from #3264