[Java][FlightSQL] Arrow Flight SQL JDBC Driver returns -1 for getUpdateCount()

### Describe the bug, including details regarding any error messages, version, and platform.

Tested on Arrow Flight JDBC 15, 15.02 and with a locally-built Arrow Flight SQL JDBC Driver 17.0.0-SNAPSHOT.

When using a JDBC statement to execute an UPDATE, the getUpdateCount() method seems to always return -1. This seems to be incorrect. The getUpdateCount() should return the number of rows UPDATEd.

For a data source, we're using the [Voltron docker container](https://hub.docker.com/r/voltrondata/flight-sql)

In this debugger image, you can see the return counts from the getUpdateCount() and from the actual result set (the update returns one row, with one column, that indicates the number of UPDATEd rows.

Here is a screen grab of the output data:

And, in this screengrab, I used the Postgres driver to update a table in postgres:latest Docker image:

The data in the Postgres table is different, but the getUpdateCount() method returned 1 which is correct for that data.
The test program I used is checked into this Github repo: [ZD128958](https://github.com/rcprcp/ZD128958)

Thank you!

### Component(s)

Java

首先针对 Arrow Flight SQL JDBC Driver 运行 ZD128958 测试程序，并将 UPDATE 返回的结果集与 Statement.getUpdateCount() 进行比较。跟踪 JDBC 驱动程序处理 UPDATE 结果的路径；当 getUpdateCount() 像 PostgreSQL 驱动程序一样报告更新行数时，即表示完成。

由索引模型根据 Issue 内容生成。