[FIX] calendar: Fix traceback when calling change_attendee_status
[FIX] calendar: Fix traceback when calling change_attendee_status

Coming from the calendar refactoring at
https://github.com/odoo/odoo/commit/39aef65f37a8ae969527b31a680eb27fddbc5710

closes odoo/odoo#52005

Signed-off-by: Yannick Tivisse (yti) <200a91eb0e5cc4726d6a3430713b580138f34298@odoo.com>

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo