[FIX] repair: correctly group invoices

Have 2 repair records with the same partner_id, ready to be invoiced
In list view select both records and click Action>Create invoices
In the wizard check 'Group by partner invoice address', create invoices.

Separate invoices will be created, but while grouping 1 invoice should
be created joining the 2 repairs

opw-2476539

closes odoo/odoo#70404

Signed-off-by: agr-odoo <agr-odoo@users.noreply.github.com>