Incompatible implementation of `json_to_record` functions

**Describe the problem**

The function `json_to_record` and friends behave differently in CockroachDB than they do in Postgres.

PostgreSQL allows you to extract any field of an object as a scalar value of type `json`, but CockroachDB does not allow string-fields to be extracted as a value of type `json`.

**To Reproduce**

On cockroachdb:
```
psql (16.0, server 13.0.0)
Type "help" for help.

defaultdb=> select t.* from json_to_record('{"field1":"string value", "field2":{"object":"value"}}') as t(field1 json, field2 json);
ERROR: could not parse JSON: unable to decode JSON: while decoding 12 bytes at offset 0:
...|string value|...
...|^...........|...: invalid JSON token
defaultdb=> select t.* from json_to_record('{"field1":"string value", "field2":{"object":"value"}}') as t(field1 text, field2 json);
field1 | field2
--------------+---------------------
string value | {"object": "value"}
(1 row)

defaultdb=>
```

**Expected behavior**
On Postgres

```
postgres=# select t.* from json_to_record('{"field1":"string value", "field2":{"object":"value"}}') as t(field1 json, field2 json);
field1 | field2
----------------+--------------------
"string value" | {"object":"value"}
(1 row)
```

**Additional data / screenshots**

Environment:
```
defaultdb=> select version();
version
--------------------------------------------------------------------------------------
CockroachDB CCL v23.1.10 (x86_64-pc-linux-gnu, built 2023/09/14 14:09:38, go1.19.10)
(1 row)
```

Jira issue: CRDB-35301