New packs without pack_type attribute

CHANGELOG:

### CHANGED
- [#893](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/nn) New packs without pack_type attribute

Related card: https://trello.com/c/5NZC9zzw/1373-creaci%C3%B3-de-nous-productes-de-pack

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