Bug 30779: Remove _update_import_record_marc and update tests

Bug 30779: Remove _update_import_record_marc and update tests

This patch removes the now unused: _update_import_record_marc

Additionally, as items are already present in import biblio we no longer need to embed
them, so that parameter is removed and the option removed from the sub and pod and everywhere
it was used

In all cases, we were embedding, so we don't need a way to get without

Tests updated

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit b02b66acf5ddac1af00215fbcc1d842777b67c3b)