bundle: include dependencies from DEFAULT column expressions

Consider the following setup:
```sql
CREATE FUNCTION f(id INT) RETURNS INT LANGUAGE SQL AS $$ SELECT id; $$;
CREATE SEQUENCE s;
CREATE TABLE t (k INT PRIMARY KEY, id INT NOT NULL DEFAULT f(nextval('s'::REGCLASS)));
```
Neither UDF `f` nor sequence `s` are included into the stmt bundle which will prevent easy recreation. We do include some dependent UDFs and sequences, so perhaps we're missing tracking of the DEFAULT column expression (maybe more).

Jira issue: CRDB-39474