`_address_fields` are used by `update_address` [1], which is in turn
called by `_fields_sync` and `_children_sync`.
This mechanism is in charge of synchronizing parent/children address fields
for contacts of type == "contact", as they don't really have an address of
their own. They simply copy the address of their parent.
Without this fix, an inconsistency is created between the value of city_id
and the value of the parent.
[1]: https://github.com/odoo/odoo/blob/20648ef21/odoo/addons/base/models/res_partner.py#L429
TT33047
closesodoo/odoo#80236
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>
