[16.0] sale_advance_payment: rounding of amount_residual

[AurelijaNorvaisaite]

Module

sale_advance_payment

Describe the bug

As odoo does not have rounding for field amount_total, in some cases amount_residual only looks like 0, but it is not. And while filtering by this field, you get:

amount_residual is:

This issue was noticed while migrating from v10, but it also happens with new orders in v16.

To Reproduce

Affected versions:

Steps to reproduce the behavior:

1. It happens when unit price is similar to this:
   

Expected behavior
It should be 0

Additional context
Fix: add digits on field amount_residual as digits="Product Price"

Also, in some cases (with custom, oca and odoo modules combined), tests fail. If should be @tagged("post_install", "-at_install") added on tests.