Incorrect IPC schema encoding for multiple dictionaries

[XiangpengHao]

Describe the bug

The following test case should pass, but it errors:

thread 'tests::test_dict_schema' panicked at arrow-flight/src/lib.rs:851:56:
called `Result::unwrap()` on an `Err` value: ParseError("Unable to convert flight info to a message: Type `i64` at position 100 is unaligned.\n\twhile verifying table field `id` at position 100\n\twhile verifying table field `dictionary` at position 76\n\twhile verifying vector element 1 at position 56\n\twhile verifying table field `fields` at position 44\n\t while verifying union variant `MessageHeader::Schema` at position 24\n\twhile verifying table field `header` at position 24\n\n")

To Reproduce

    #[test]
    fn test_dict_schema() {
        let schema = Schema::new(vec![
            Field::new(
                "a",
                DataType::Dictionary(Box::new(DataType::UInt16), Box::new(DataType::Utf8)),
                false,
            ),
            Field::new(
                "b",
                DataType::Dictionary(Box::new(DataType::UInt16), Box::new(DataType::Utf8)),
                false,
            ),
        ]);

        let flight_info = FlightInfo::new().try_with_schema(&schema).unwrap();

        let new_schema = Schema::try_from(flight_info).unwrap();
        assert_eq!(schema, new_schema);
    }

Expected behavior

If the schema only has one dictionary, it would work just fine.

Additional context

[XiangpengHao]

Update: my latest finding is that it will panic whenever the dict_id is not 0

Probably related to: #5981