Bug 31224: Revert to $metadata->record in `marcrecord2csv`

Bug 31224: Revert to $metadata->record in `marcrecord2csv`

This patch reverts the change for marcrecord2csv as
`$biblio->metadata_record` doesn't support a list of itemnumbers, and it
feels we should discuss in another context whether to add it as a
parameter, or make it a Koha::Items iterator. The Koha::Item object is
actually retrieved in marc2csv so there's room for easy improvements
without adding technical debt (i.e. bad method signatures for a single
use case).

This fixes a feature:

1. Run:
   $ ktd --shell
  k$ prove t/db_dependent/Exporter/Record.t
=> FAIL: Test fails because the 'items' are not being filtered on the
passed itemnumbers (i.e. all items are picked for generating the CSV).
2. Apply this patch
3. Repeat 1
=> SUCCESS: Tests pass!

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>