Fix permalinks to point to topic-url and not to first post of topic

[cocococosti (Constanza Abarca)]

@rrit

After a customized migration many permalinks were pointing to the first post in a topic instead of the topic-url itself.

How did you create the permalinks?

For example, here discourse/script/import_scripts/vanilla_mysql.rb at main · discourse/discourse · GitHub they specifically check the post number, if it’s 1, then the post_is not passed (left as NULL) and thus the permalink shouldn’t point to the first post.