JSON_ARRAYAGG reprot unsupported second argument type

[xiongjiwei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

CREATE TABLE t1 (a FLOAT, b DOUBLE, c DECIMAL(10, 2));
INSERT INTO t1 VALUES (1.0, 2.0, 3.0),(1.0, 3.0, 9.0),(1.0, 4.0, 16.0),(1.0, 5.0, 25.0);
SELECT JSON_VALID(JSON_ARRAYAGG(a)) FROM t1;

2. What did you expect to see? (Required)

3. What did you see instead (Required)

mysql> SELECT JSON_VALID(JSON_ARRAYAGG(a)) FROM t1;
ERROR 8066 (HY000): JSON_OBJECTAGG: unsupported second argument type 1

4. What is your TiDB version? (Required)