[FIX] account: partially revert 3754280a

The changes should not have been merged in stable.
Users installing the account module before 3754280a had a not null constraint
on the field company_id.

After updating the code, the field is still required but has no default value.

If a chart of account is installed after updating the code, it would fail.

opw-1867358

addons/account/models/chart_template.py

@@ -510,7 +510,7 @@ class AccountTaxTemplate(models.Model):
     amount_type = fields.Selection(default='percent', string="Tax Computation", required=True,
         selection=[('group', 'Group of Taxes'), ('fixed', 'Fixed'), ('percent', 'Percentage of Price'), ('division', 'Percentage of Price Tax Included')])
     active = fields.Boolean(default=True, help="Set active to false to hide the tax without removing it.")
-    company_id = fields.Many2one('res.company', string='Company')
+    company_id = fields.Many2one('res.company', string='Company', default=lambda self: self.env.user.company_id)
     children_tax_ids = fields.Many2many('account.tax.template', 'account_tax_template_filiation_rel', 'parent_tax', 'child_tax', string='Children Taxes')
     sequence = fields.Integer(required=True, default=1,
         help="The sequence field is used to define order in which the tax lines are applied.")