Bug Report: Regression in subquery planning wrt v18

[GuptaManan100]

Overview of the Issue

The following query would work as expected in v18, but now fails in main - select col, trim((select user_name from user where id = 3)) val from user_extra where user_id = 3 group by col order by val

Plan from v18 -

{
          "QueryType": "SELECT",
          "Original": "select col, trim((select user_name from user where id = 3)) val from user_extra where user_id = 3 group by col order by val",
          "Instructions": {
            "OperatorType": "Route",
            "Variant": "EqualUnique",
            "Keyspace": {
              "Name": "user",
              "Sharded": true
            },
            "FieldQuery": "select col, trim((select user_name from `user` where 1 != 1)) as val from user_extra where 1 != 1 group by col",
            "Query": "select col, trim((select user_name from `user` where id = 3)) as val from user_extra where user_id = 3 group by col order by trim((select `user`.user_name from `user` where `user`.id = 3)) asc",
            "Table": "user_extra",
            "Values": [
              "3"
            ],
            "Vindex": "user_index"
          },
          "TablesUsed": [
            "user.user",
            "user.user_extra"
          ]
        }

The error in main -

"VT12001: unsupported: subquery with aggregation in order by"

Reproduction Steps

Run the given query in the plan_test on main and v18

Binary Version

main, 20, 19

Operating System and Environment details

-

Log Fragments

No response