Avoid relying on non-deterministic ordering on test_group_edit_loads_with_page_permissions_shown

wagtail/wagtailusers/tests.py

@@ -587,8 +587,8 @@ class TestGroupEditView(TestCase, WagtailTestUtils):
             self.root_page.pk
         )
         self.assertEqual(
-            page_permissions_formset.forms[0]['permission_types'].value(),
-            ['add', 'edit']
+            set(page_permissions_formset.forms[0]['permission_types'].value()),
+            set(['add', 'edit'])
         )
         self.assertEqual(
             page_permissions_formset.forms[1]['page'].value(),