bug: internal table doesn't display correctly

[zwang28]

Describe the bug

PK is partition_id, but count(*) > count(distinct(partition_id)), i.e. a single row repeats multiple times.

dev=> describe __internal_some_table_123_source_123;
       Name        |                             Type                             | Is Hidden | Description
-------------------+--------------------------------------------------------------+-----------+-------------
 partition_id      | character varying                                            | false     |
 offset_info       | jsonb                                                        | false     |
 primary key       | partition_id                                                 |           |
 table description | __internal_some_table_123_source_123 |           |
(4 rows)

dev=> select count(distinct(partition_id))  from __internal_some_table_123_source_123;
 count
-------
    73
(1 row)

dev=> select count(*)  from __internal_some_table_123_source_123;
 count
-------
 17520
(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

[BugenZhao]

Is this related to #5590?