[FIX] fields: *2many convert_to_cache for new records
[FIX] fields: *2many convert_to_cache for new records

When interpreting commands, the initial value for new records is an empty list.
This regression was introduced by 09397384795f440b5924d9b325988e9cc6eb4d09.

Fixes #11239.

Elico-Corp/odoo_OCB,laslabs/odoo,microcom/odoo,stephen144/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,stephen144/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,laslabs/odoo,sysadminmatmoz/OCB,storm-computers/odoo,ygol/odoo,laslabs/odoo,stephen144/odoo,storm-computers/odoo,ygol/odoo,stephen144/odoo,bplancher/odoo,bplancher/odoo,storm-computers/odoo,microcom/odoo,Elico-Corp/odoo_OCB,sysadminmatmoz/OCB,bplancher/odoo,ygol/odoo,laslabs/odoo,hip-odoo/odoo,hip-odoo/odoo,storm-computers/odoo,hip-odoo/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,dfang/odoo,sysadminmatmoz/OCB,stephen144/odoo,laslabs/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,sysadminmatmoz/OCB,Elico-Corp/odoo_OCB,hip-odoo/odoo,dfang/odoo,microcom/odoo,microcom/odoo,dfang/odoo,microcom/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,dfang/odoo,storm-computers/odoo,storm-computers/odoo,ygol/odoo,ygol/odoo,sysadminmatmoz/OCB,sysadminmatmoz/OCB,stephen144/odoo,ygol/odoo,microcom/odoo,ygol/odoo,laslabs/odoo