Tuple data received from nodes should be 0 for local execution

The following plan shows "Tuple data received from nodes: 29 bytes" for the outer plan, but the task is executed locally so there is no network traffic.

```sql
EXPLAIN ANALYZE WITH a AS (SELECT * FROM test LIMIT 10) SELECT * FROM a;
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ QUERY PLAN │
├────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ Custom Scan (Citus Adaptive) (cost=0.00..0.00 rows=0 width=0) (actual time=9.636..9.638 rows=10 loops=1) │
│ -> Distributed Subplan 4_1 │
│ Subplan Duration: 17.07 ms │
│ Intermediate Data Size: 168 bytes │
│ Result destination: Write locally │
│ -> Limit (cost=0.00..0.00 rows=10 width=8) (actual time=10.680..10.682 rows=10 loops=1) │
│ -> Custom Scan (Citus Adaptive) (cost=0.00..0.00 rows=100000 width=8) (actual time=10.678..10.679 rows=10 loops=1) │
│ Task Count: 32 │
│ Tuple data received from nodes: 557 bytes │
│ Tasks Shown: One of 32 │
│ -> Task │
│ Tuple data received from node: 15 bytes │
│ Node: host=localhost port=9700 dbname=postgres │
│ -> Limit (cost=0.00..0.14 rows=10 width=8) (actual time=0.007..0.008 rows=6 loops=1) │
│ -> Seq Scan on test_102008 test (cost=0.00..32.60 rows=2260 width=8) (actual time=0.006..0.007 rows=6 loops=1) │
│ Planning Time: 0.021 ms │
│ Execution Time: 0.018 ms │
│ Planning Time: 0.000 ms │
│ Execution Time: 11.156 ms │
│ Task Count: 1 │
│ Tuple data received from nodes: 29 bytes │
│ Tasks Shown: All │
│ -> Task │
│ Tuple data received from node: 29 bytes │
│ Node: host=localhost port=5432 dbname=postgres │
│ -> Function Scan on read_intermediate_result intermediate_result (cost=0.00..0.07 rows=9 width=8) (actual time=0.091..0.092 rows=10 loops=1) │
│ Planning Time: 0.044 ms │
│ Execution Time: 0.114 ms │
│ Planning Time: 1.352 ms │
│ Execution Time: 28.411 ms │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(30 rows)

```