plpgsql: plpgsql procedures don't apply the correct param ord to params

When assigning the "paramOrd" to `optBuilder` scope columns allocated to represent the parameters to a PL/pgSQL routine, currently we skip over `OUT` params. This is correct for SQL, but not for PL/pgSQL routines, which are able to reference OUT params both by name and by ordinal position. For example, this test currently fails with `(42P02) no value provided for placeholder: $2`:
```
statement ok
CREATE OR REPLACE PROCEDURE p(OUT o INT, IN i INT)
AS $$ BEGIN o := $2; END; $$ LANGUAGE PLpgSQL;

query I
CALL p(NULL, 42);
----
42
```

Jira issue: CRDB-60868