Fix: default partner_bank_id in contract_address_change wizard
CHANGELOG:
### Fixed
- [#1179](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/1179): Fix default IBAN with contract address change: take the one from the current mandate id instead of the first from the partner's list.
Related card: https://trello.com/c/hbCWdjB4/1839-fix-default-mandate-location-change-wizard
Edited by Gerard Funosas