[FIX] hr: activity type responsible on hr plans

fine-tuning of bf8a9af1

- Employees > Configuration > Activity Planning > Plans and ensure the
  activities have different responsible;
- Create a new Employee, assign a Manager (a different user then the one
  connected, you can assign Marc Demo for example);
- Click launch plan.

Before this commit, the activity type responsible is ignored and the
responsible for all activities is the connected user.

Now, the responsible for the activities are assigned taking into account
the activity type configuration.

opw-2265631

closes odoo/odoo#54033

Signed-off-by: Jorge Pinna Puissant (jpp) <jpp@odoo.com>

addons/hr/wizard/hr_plan_wizard.py

@@ -33,6 +33,7 @@ class HrPlanWizard(models.TransientModel):
                     'user_id': responsible.id,
                 })
                 activity._onchange_activity_type_id()
+                activity.user_id = responsible.id
 
         return {
             'type': 'ir.actions.act_window',