Remove from logical children and clear item container on reset (#15855)

* Remove from logical children and clear item container on reset (similarly like OnItemsChanged.Remove)

* Add simple test

---------

Co-authored-by: Meloman19 <23280622+Meloman19@users.noreply.github.com>

src/Avalonia.Controls/Presenters/PanelContainerGenerator.cs

@@ -136,12 +136,15 @@ namespace Avalonia.Controls.Presenters
                 return;
 
             var itemsControl = _presenter.ItemsControl;
+            var generator = itemsControl.ItemContainerGenerator;
             var panel = _presenter.Panel;
 
             foreach (var c in panel.Children)
             {
+                itemsControl.RemoveLogicalChild(c);
+
                 if (!c.IsSet(ItemIsOwnContainerProperty))
-                    itemsControl.RemoveLogicalChild(c);
+                    generator.ClearItemContainer(c);
             }
         }
     }

tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs

@@ -976,6 +976,29 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(1, raised);
         }
 
+        [Fact]
+        public void ContainerClearing_Is_Raised_When_ItemsSource_Is_Cleared()
+        {
+            using var app = Start();
+            var itemsSource = new ObservableCollection<object> { "Foo", "Bar", "Baz" };
+            var target = CreateTarget(itemsSource: itemsSource);
+
+            var expectedContainers = itemsSource.Select(x => target.ContainerFromItem(x)).ToArray();
+            var actualContainers = new List<Control>();
+            var raised = 0;
+
+            target.ContainerClearing += (s, e) =>
+            {
+                actualContainers.Add(e.Container);
+                ++raised;
+            };
+
+            itemsSource.Clear();
+
+            Assert.Equal(3, raised);
+            Assert.Equal(expectedContainers, actualContainers);
+        }
+
         [Fact]
         public void Handles_Recycling_Control_Items_Inside_Containers()
         {