bug: empty definition for create table as select

[zwang28]

Describe the bug

create table tt2 (a int, b int);
create table tt as select * from tt2;

dev=> select definition from rw_tables where name='tt';
 definition 
------------
 
(1 row)

dev=> show create table tt;
   Name    | Create Sql 
-----------+------------
 public.tt | 
(1 row)

Error message/log

No response

To Reproduce

No response

Expected behavior

No response

How did you deploy RisingWave?

No response

The version of RisingWave

No response

Additional context

No response

[zwang28]

duplicate of #15334