[FIX] sale_timesheet: choose the project's company to determine cost

Companies:
B child of A

User:
Demo in B not in A
Admin in A

Create a product with Admin:
track service = timesheet on project
invoicing policy = delivered quantities

Create a SO with Demo and validate, a project is created
Now, make the demo user timzsheet on it

Before this commit, there was an access error on company,
that was because the the company that was choosen to determine the cost, was the one on the employee, which could be
in another company than the user and moreover than the project

After this commit, we take the company of the project

OPW 1871440
closes #26271

addons/sale_timesheet/models/account.py

@@ -38,10 +38,10 @@ class AccountAnalyticLine(models.Model):
                 return {}
             unit_amount = values.get('unit_amount', 0.0) or self.unit_amount
             user_id = values.get('user_id') or self.user_id.id or self._default_user()
-            user = self.env['res.users'].browse([user_id])
+            project = values.get('project_id') and self.env['project.project'].browse([values['project_id']]) or self.project_id
             emp = self.env['hr.employee'].search([('user_id', '=', user_id)], limit=1)
             cost = emp and emp.timesheet_cost or 0.0
-            uom = (emp or user).company_id.project_time_mode_id
+            uom = project.company_id.project_time_mode_id
             # Nominal employee cost = 1 * company project UoM (project_time_mode_id)
             return {
                 'amount': -unit_amount * cost,