[FIX] analytic: view all plans on view subplans

To reproduce:
- Activate analytic accounting
- Create an analytic plan
- Click on Subplans
- Create a Subplan
- Come back to the list view of subplans (with the breadcrumb)
=> The new plan does not appear

The children_ids are not recomputed, so we inverse the logic.

task-3359643

closes odoo/odoo#124404

Signed-off-by: William André (wan) <wan@odoo.com>

addons/analytic/models/analytic_plan.py

@@ -120,7 +120,7 @@ class AccountAnalyticPlan(models.Model):
         result = {
             "type": "ir.actions.act_window",
             "res_model": "account.analytic.plan",
-            "domain": [('id', 'in', self.children_ids.ids)],
+            "domain": [('parent_id', '=', self.id)],
             "context": {'default_parent_id': self.id,
                         'default_color': self.color},
             "name": _("Analytical Plans"),