[FIX] account: coherent force_price_include=False

Before this commit, using context key `force_price_include=False` had
different interpretations in different methods

In `compute_all` its semantic was forcing the "price_include" of taxes
to be False
In `_compute_amount` it was ignored (as only value "True" was overriding
anything)

To add to this incoherence, compute_all does use
`force_price_include=False` when calling `_compute_amount`.

This commits brings semantical coherence to the `account_tax` methods by
keeping both interpretations of the context key the same: an override of
price_include, whether its value True or False.

This fixes a ticket in which the client uses that override to inverse
the computation of `price_unit` from a tax-excluded counterpart.

owp-3770871

closes odoo/odoo#155813

X-original-commit: 9b852b29e94bf0522f1b041caf12fa648ceb13c6
Signed-off-by: Laurent Smet (las) <las@odoo.com>

addons/account/models/account_tax.py

@@ -809,7 +809,7 @@ class AccountTax(models.Model):
                 if tax.include_base_amount:
                     base = recompute_base(base, incl_tax_amounts)
                     store_included_tax_total = True
-                if tax.price_include or self._context.get('force_price_include'):
+                if self._context.get('force_price_include', tax.price_include):
                     if tax.amount_type == 'percent':
                         incl_tax_amounts['percent_taxes'].append((i, tax.amount * sum_repartition_factor))
                     elif tax.amount_type == 'division':