[FIX] account: prevent from changing partner's company

When changing the company of a partner, if the latter still has some
unreconciled AML, it will lead to a display error on follow-up report

To reproduce the error:
(Need account_accountant. Let C01 be the current company, its currency
is USD)
1. In Settings, enable:
    - Multi-currencies
    - Multi-companies
2. Create a second company C02
    - Currency: EUR
3. Create a partner P linked to company C01
4. Invoice P with X EUR (!)
5. Open the tree view of the follow-up report:
    - P is present in the list with amount Y USD (X has been converted
to C01's company)
6. Edit P
    - Company: C02
7. Open the tree view of the follow-up report

Error: The amount is Y EUR which is incorrect (it should be either Y USD
or X EUR)

The currency used to display the amount is the partner's currency
https://github.com/odoo/odoo/blob/bc53c49c08d48179a7e2d927f3e2b7ba92e77d6c/addons/account/models/partner.py#L391-L391
https://github.com/odoo/odoo/blob/bc53c49c08d48179a7e2d927f3e2b7ba92e77d6c/addons/account/models/partner.py#L377-L382


This is the reason why the display becomes incorrect

Changing a partner's company does not make sense and should not be
allowed

OPW-2525793

closes odoo/odoo#72977

Signed-off-by: William André (wan) <wan@odoo.com>