changefeedccl: inconsistent fully qualified table names after alter add table

After an alter changefeed, the table names in the create changefeed statement have inconsistent qualified names. The table qualified name should be consistent.

To repro:
```
create table t (i int);
create table v (i int);
create changefeed for table t into 'null://';
show changefeed jobs;
# CREATE CHANGEFEED FOR TABLE t INTO 'null:'
pause job [job id];
alter changefeed [job id] add table v;
# CREATE CHANGEFEED FOR TABLE defaultdb.public.t, TABLE v INTO 'null:'
show changefeed jobs;
# CREATE CHANGEFEED FOR TABLE defaultdb.public.t, TABLE v INTO 'null:'
```

Jira issue: CRDB-51206