[bug](function)fix json_replace check return type error

[zhangstar333]

Proposed changes

1. fix the return type dcheck error:

mysql [test]>select (json_replace(a, '$.fparam.nested_2', "qwe")) from json_table_2 limit 1;
ERROR 1105 (HY000): errCode = 2, detailMessage = (10.16.10.8)[INTERNAL_ERROR]Function json_replace get failed, expr is VectorizedFnCall[json_replace](arguments=a, String, String, String,return=Nullable(String)) and return type is Nullable(String).

2. improve the json_replace/json_insert/json_set function execute of not convert const column, test about could faster 1s on 1000w table rows