Cannot cast string dictionary to binary view

[Jefffrey]

Describe the bug

When casting a dictionary with string value to binary view, run into an unexpected error.

To Reproduce

This test should pass:

// arrow-cast/src/cast/mod.rs
    #[test]
    fn test_string_dict_to_binary_view() {
        let values = StringArray::from_iter(VIEW_TEST_DATA);
        let keys = Int8Array::from_iter([Some(1), Some(0), None, Some(3), None, Some(1), Some(4)]);
        let string_dict_array =
            DictionaryArray::<Int8Type>::try_new(keys, Arc::new(values)).unwrap();

        let casted = cast(&string_dict_array, &DataType::BinaryView).unwrap();
        assert_eq!(casted.data_type(), &DataType::BinaryView);
    }

Currently failing:

thread 'cast::tests::test_string_dict_to_binary_view' (4994586) panicked at arrow-cast/src/cast/mod.rs:6651:70:
called `Result::unwrap()` on an `Err` value: ComputeError("Internal Error: Cannot cast BinaryView to BinaryArray of expected type")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
test cast::tests::test_string_dict_to_binary_view ... FAILED

Expected behavior

Should successfully cast to a binary view.

Additional context

Discovered in DataFusion: apache/datafusion#18662 (comment)

Related code is here:

arrow-rs/arrow-cast/src/cast/dictionary.rs

Lines 107 to 125 in 2bc269c

	BinaryView => {
	// `unpack_dictionary` can handle Utf8View/BinaryView types, but incurs unnecessary data copy of the value buffer.
	// we handle it here to avoid the copy.
	let dict_array = array
	.as_dictionary::<K>()
	.downcast_dict::<BinaryArray>()
	.ok_or_else(|| {
	ArrowError::ComputeError(
	"Internal Error: Cannot cast BinaryView to BinaryArray of expected type"
	.to_string(),
	)
	})?;
	let binary_view = view_from_dict_values::<K, BinaryViewType, BinaryType>(
	dict_array.values(),
	dict_array.keys(),
	)?;
	Ok(Arc::new(binary_view))
	}

• It's likely the same will happen for vice-versa situation, i.e. binary dictionary to string view (see above arm)

Related PR: #5871

[Jefffrey]

If I comment out the BinaryView arm in the related code, the test passes successfully.

[alamb]

label_issue.py automatically added labels {'arrow'} from #8912