Fix chunk download failures mis-bucketed as CONNECTION_ERROR in telemetry (#1469)

## Summary

The 5-arg `DatabricksSQLException(reason, cause, statementId,
chunkIndex, sqlState)` constructor — used exclusively by
`ChunkDownloadTask` — hardcoded `CONNECTION_ERROR.name()` in its
`exportFailureLog` call, ignoring the `sqlState` argument passed in by
the caller.

`ChunkDownloadTask.java:98` passes `CHUNK_DOWNLOAD_ERROR.name()` as
`sqlState`, so chunk download failures were:
- stored on the `SQLException` with sqlState `CHUNK_DOWNLOAD_ERROR`
(visible to JDBC consumers), but
- recorded in telemetry under the `CONNECTION_ERROR` bucket.

This divergence was flagged by a pre-existing `// TODO : Check chunk
retry telemetry logic` comment.

The fix passes the caller's `sqlState` through to `exportFailureLog`, so
the telemetry `errorName` matches the SQLException's sqlState and the
caller's intent.

## Test plan

- [ ] `mvn test -pl . -Dtest=ChunkDownloadTaskTest`
- [ ] `mvn test -pl . -Dtest=DatabricksSQLExceptionTest`
- [ ] Confirm telemetry dashboards bucket chunk download failures under
`CHUNK_DOWNLOAD_ERROR` going forward (was `CONNECTION_ERROR`).

NO_CHANGELOG=true

This pull request and its description were written by Isaac.

Signed-off-by: samikshya-chand_data <samikshya.chand@databricks.com>

Author: samikshya-db

src/main/java/com/databricks/jdbc/exception/DatabricksSQLException.java

@@ -27,14 +27,14 @@ public DatabricksSQLException(String reason, Throwable cause, String sqlState) {
     this(reason, sqlState, DatabricksVendorCode.getVendorCode(cause), cause);
   }
 
-  // This constructor is used to export chunk download failure logs
-  // TODO : Check chunk retry telemetry logic
+  // Chunk-download path: routes statementId + chunkIndex into the telemetry record so failures
+  // can be bucketed per chunk. Other constructors do not carry chunkIndex.
   public DatabricksSQLException(
       String reason, Throwable cause, String statementId, Long chunkIndex, String sqlState) {
     super(reason, sqlState, DatabricksVendorCode.getVendorCode(cause), cause);
     exportFailureLog(
         DatabricksThreadContextHolder.getConnectionContext(),
-        DatabricksDriverErrorCode.CONNECTION_ERROR.name(),
+        sqlState,
         reason,
         statementId,
         chunkIndex,