Custom function mutations nor returning setof should be without where/limits/distinct

### Version Information

Server Version:
v2.11.1-cloud.2

### Environment

Cloud/ OSS

### What is the current behaviour?

Hasura can track mutation from custom volatile postgres function that returns single object (not an array)

```
CREATE OR REPLACE FUNCTION myMutation(name text) RETURNS tbl1 LANGUAGE plpgsql AS
$$
BEGIN
INSERT INTO
tbl1(name)
VALUES
(name) RETURNING ret;
RETURN ret;
END;
$$
```

### What is the expected behaviour?

Just `arg: {name}` for this mutation in graphql schema - without `where: {} limit distint`

### How to reproduce the issue?

1. create and track posgres function as mutation
2. check graphql schema / graphqil

### Screenshots or Screencast
graphiql doc view: