Add inactive_sponsored field to get Partner API response

CHANGELOG:

### Added
- [#nn](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/nn) Add inactive_sponsored field to get Partner API response

Related card: https://trello.com/c/tdwLeBit/416-controlar-que-un-apadrinado-no-activo-contrata-nuevos-servicios

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