[FIX] account: decimal separator on vendor bill

Steps to reproduce:

- Set a language which use ',' (comma) as
  decimal separator (eg French)
- Make a Vendor Bill for any product at any price.

If the partner's language use '.' (period) as
decimal separator (eg English), the field
amount_by_group is formated whit period, while others
are formated with comma. They should all be formated
with comma.

- Now print the Vendor Bill

The same issue is occuring.

With Customer Invoices, the issue is the same on
the form view, but not on the printing, where all
the fields are formated with period, as set in the
partner's language.

After this commit, we format all the fields
regarding the environment's language on the view form,
either in Vendor Bills and Customer Invoices,
and we formating the printed bill/invoice regarding
the partner's language

opw-2735698

closes odoo/odoo#84284

Signed-off-by: Florian Gilbert <flg@odoo.com>