[FIX] models: log field names in api.onchange warning

Without this, the warning isn't very actionable.

closes odoo/odoo#75847

X-original-commit: afe7c989
Signed-off-by: Olivier Dony (odo) <odo@openerp.com>
Signed-off-by: Wolfgang Taferner <wtaferner@users.noreply.github.com>