Fix foreign_key_to_reference_shard_rebalance test (#7400)

foreign_key_to_reference_shard_rebalance failed because partition of
2024 year does not exist, fixed by add default partition.

Co-authored-by: chuhx <148182736+cstarc1@users.noreply.github.com>
(cherry picked from commit 968ac74cde)

src/test/regress/expected/foreign_key_to_reference_shard_rebalance.out

@@ -210,7 +210,7 @@ select create_distributed_table('partitioned_tbl_with_fkey','x');
 
 create table partition_1_with_fkey partition of partitioned_tbl_with_fkey for values from ('2022-01-01') to ('2022-12-31');
 create table partition_2_with_fkey partition of partitioned_tbl_with_fkey for values from ('2023-01-01') to ('2023-12-31');
-create table partition_3_with_fkey partition of partitioned_tbl_with_fkey for values from ('2024-01-01') to ('2024-12-31');
+create table partition_3_with_fkey partition of partitioned_tbl_with_fkey DEFAULT;
 insert into partitioned_tbl_with_fkey (x,y) select s,s%10 from generate_series(1,100) s;
 ALTER TABLE partitioned_tbl_with_fkey ADD CONSTRAINT fkey_to_ref_tbl FOREIGN KEY (y) REFERENCES ref_table_with_fkey(id);
 WITH shardid AS (SELECT shardid FROM pg_dist_shard where logicalrelid = 'partitioned_tbl_with_fkey'::regclass ORDER BY shardid LIMIT 1)

src/test/regress/sql/foreign_key_to_reference_shard_rebalance.sql

@@ -84,7 +84,7 @@ create table partitioned_tbl_with_fkey (x int, y int, t timestamptz default now(
 select create_distributed_table('partitioned_tbl_with_fkey','x');
 create table partition_1_with_fkey partition of partitioned_tbl_with_fkey for values from ('2022-01-01') to ('2022-12-31');
 create table partition_2_with_fkey partition of partitioned_tbl_with_fkey for values from ('2023-01-01') to ('2023-12-31');
-create table partition_3_with_fkey partition of partitioned_tbl_with_fkey for values from ('2024-01-01') to ('2024-12-31');
+create table partition_3_with_fkey partition of partitioned_tbl_with_fkey DEFAULT;
 insert into partitioned_tbl_with_fkey (x,y) select s,s%10 from generate_series(1,100) s;
 
 ALTER TABLE partitioned_tbl_with_fkey ADD CONSTRAINT fkey_to_ref_tbl FOREIGN KEY (y) REFERENCES ref_table_with_fkey(id);