RE: sequencesync worker race with REFRESH SEQUENCES

Dear Vignesh,

Thanks for attaching the patch. I think there is a corner case that ALTER
SERVER command changes the connection to the pre-PG19 server.

Firstly, we can create a server for connecting to the PG19 server:
CREATE SERVER server ... OPTIONS (...);

Then we can use the SERVER in the subscription definition:
CREATE SUBSCRIPTION sub SERVER server ...;

After that, we can alter the SERVER to connect to the PG18 server:
ALTER SERVER server OPTION (SET dbname 'postgres' port '5434');

If users run the ALTER SUBSCRITPION REFRESH SEQUENCES command, it could succeed
but the worker will raise the ERROR periodically.

```
ERROR: invalid query response
DETAIL: Expected 11 fields, got 10 fields.
LOG: background worker "logical replication sequencesync worker" (PID 2269290) exited with exit code 1
```

Above can be reported because pg_get_sequence_data() has been available since
PG18 but the returned datatype was different.

Best regards,
Hayato Kuroda
FUJITSU LIMITED