fix: carry process id in query ctx (#6335)

fix/carry-process-id-in-query-ctx:
 ### Commit Message

 Enhance query context handling in `instance.rs`

 - Updated `Instance` implementation to include `process_id` in query context initialization, improving traceability and debugging capabilities.

Signed-off-by: Lei, HUANG <mrsatangel@gmail.com>

src/frontend/src/instance.rs

@@ -185,7 +185,7 @@ impl Instance {
             vec![query_ctx.current_schema()],
             stmt.to_string(),
             query_ctx.conn_info().to_string(),
-            None,
+            Some(query_ctx.process_id()),
         );
 
         let query_fut = async {