create_distributed_table needs dependent sequence owned by the user

Although PG allows to create table even if the dependent sequence is not owned by the user, Citus enforces it.

```sql
CREATE SEQUENCE my_seq;

CREATE USER test_user;
SELECT run_command_on_workers($$CREATE USER test_user;$$);

SET ROLE test_user;
CREATE TABLE dist_table(a int, b int DEFAULT nextval('my_seq'));

SELECT create_distributed_table('dist_table', 'a');
ERROR: must be owner of sequence my_seq
```