The note was made to explain why the feature is disabled and it wasn't
removed when it was enabled later on.

Since there are no longer other logs than the dnf5.log, some scenarios
or parts of tests that tested these logs are removed.

Dnf5 doesn't print the whole messages from librepo on stdout, it instead
prints them on stderr, plus they are truncated, possibly because there
can be many errors from librepo at once, for example due to trying many
mirrors. The full message is then in the dnf5.log.

There is no point in testing that the behavior is incorrect and having
just a note about the correct one.

There is no reason to test that dnf stores internal information in
a specific place.