Remove unneeded closing check (#1910)

Author: AZero13

src/Calculator/Views/Calculator.xaml

@@ -690,6 +690,7 @@
                     <Flyout x:Name="HistoryFlyout"
                             AutomationProperties.AutomationId="HistoryFlyout"
                             Closed="HistoryFlyout_Closed"
+                            Closing="HistoryFlyout_Closing"
                             FlyoutPresenterStyle="{StaticResource HistoryFlyoutStyle}"
                             Opened="HistoryFlyout_Opened"
                             Placement="Full"/>
@@ -788,6 +789,7 @@
                                 x:Uid="MemoryFlyout"
                                 AutomationProperties.AutomationId="MemoryFlyout"
                                 Closed="OnMemoryFlyoutClosed"
+                                Closing="OnMemoryFlyoutClosing"
                                 FlyoutPresenterStyle="{StaticResource MemoryFlyoutStyle}"
                                 Opened="OnMemoryFlyoutOpened"
                                 Placement="Full"/>

src/Calculator/Views/Calculator.xaml.cs

@@ -225,12 +225,6 @@ private void OnLoaded(object sender, RoutedEventArgs e)
             string memoryPaneName = AppResourceProvider.GetInstance().GetResourceString("MemoryPane");
             MemoryFlyout.FlyoutPresenterStyle.Setters.Add(new Setter(AutomationProperties.NameProperty, memoryPaneName));
 
-            if (Windows.Foundation.Metadata.ApiInformation.IsEventPresent("Windows.UI.Xaml.Controls.Primitives.FlyoutBase", "Closing"))
-            {
-                HistoryFlyout.Closing += HistoryFlyout_Closing;
-                MemoryFlyout.Closing += OnMemoryFlyoutClosing;
-            }
-
             // Delay load things later when we get a chance.
             WeakReference weakThis = new WeakReference(this);
             _ = this.Dispatcher.RunAsync(
@@ -650,9 +644,6 @@ private void HistoryFlyout_Closing(FlyoutBase sender, FlyoutBaseClosingEventArgs
 
         private void HistoryFlyout_Closed(object sender, object args)
         {
-            // Ideally, this would be renamed in the Closing event because the Closed event is too late.
-            // Closing is not available until RS1+ so we set the name again here for TH2 support.
-            AutomationProperties.SetName(HistoryButton, m_openHistoryFlyoutAutomationName);
             m_fIsHistoryFlyoutOpen = false;
             EnableControls(true);
             if (HistoryButton.IsEnabled && HistoryButton.Visibility == Visibility.Visible)
@@ -745,9 +736,6 @@ private void OnMemoryFlyoutClosing(FlyoutBase sender, FlyoutBaseClosingEventArgs
 
         private void OnMemoryFlyoutClosed(object sender, object args)
         {
-            // Ideally, this would be renamed in the Closing event because the Closed event is too late.
-            // Closing is not available until RS1+ so we set the name again here for TH2 support.
-            AutomationProperties.SetName(MemoryButton, m_openMemoryFlyoutAutomationName);
             m_fIsMemoryFlyoutOpen = false;
             EnableControls(true);
             if (MemoryButton.IsEnabled)