[FIX] l10n_pe_edi: Gain and Loss exchange rate accounts are on the opposite field by default

Issue:

When activating the multicurrency in PE, the default exchange rate accounts are placed in the opposite fields (gain account should be an income account and loss account should be an expense), currently they're the other way around.

Fix:

Change the default account so Odoo created the journal entries for exchange rate differences the correct way.

Task Latam: https://latam-localizations.odoo.com/web#id=967&menu_id=88&cids=1&action=188&model=project.task&view_type=form

Reference:

https://www.noticierocontable.com/diferencia-de-cambio-venta/
https://www.noticierocontable.com/asiento-contable-perdida-diferencia-cambio/



closes odoo/odoo#112041

Signed-off-by: Josse Colpaert <jco@odoo.com>