Portdb: don't copy a table that gets rebuilt

[DMRobertson]

The table itself is fine to port over AFAICS:

CREATE TABLE IF NOT EXISTS users_in_public_rooms (
    user_id TEXT NOT NULL,
    room_id TEXT NOT NULL
);

But I think the user directory is deliberately rebuilt after porting (the FTS tables aren't portable).

Typo 1 introduced in #2375, moved in #7711, then changed to typo 2 in #7717.

[clokep]

Typo introduced in #7717.

A different typo existed before that. 😢

[DMRobertson]

Port db tests were happy, ignoring what I assume to be sytest flakes.