[FIX] hr_expense: Fix employee_id search domain

Fix a bug introduced where the search domain returned is a string instead of
a list on the employee_id

task-3358176

Part-of: odoo/odoo#130244

addons/hr_expense/models/hr_employee.py

@@ -45,7 +45,7 @@ class Employee(models.Model):
 
         res = [('id', '=', 0)] # Nothing accepted by domain, by default
         if self.user_has_groups('hr_expense.group_hr_expense_user') or self.user_has_groups('account.group_account_user'):
-            res = "['|', ('company_id', '=', False), ('company_id', '=', company_id)]"  # Then, domain accepts everything
+            res = ['|', ('company_id', '=', False), ('company_id', 'child_of', self.env.company.root_id.id)]  # Then, domain accepts everything
         elif self.user_has_groups('hr_expense.group_hr_expense_team_approver') and self.env.user.employee_ids:
             user = self.env.user
             employee = self.env.user.employee_id