fix: memory leak of some controls. (#1482)

src/Shared/HandyControlDemo_Shared/UserControl/Controls/ImageBrowserDemoCtl.xaml

@@ -8,7 +8,7 @@
              xmlns:hc="https://handyorg.github.io/handycontrol">
     <hc:TransitioningContentControl>
         <StackPanel Margin="32">
-            <hc:ImageViewer Background="{DynamicResource SecondaryRegionBrush}" MaxWidth="600" Height="330" ImageSource="/HandyControlDemo;component/Resources/Img/1.jpg"/>
+            <hc:ImageViewer x:Name="ImageViewerDemo" Background="{DynamicResource SecondaryRegionBrush}" MaxWidth="600" Height="330" ImageSource="/HandyControlDemo;component/Resources/Img/1.jpg"/>
             <Button Margin="0,32,0,0" Command="{Binding OpenImgCmd}" Content="{ex:Lang Key={x:Static langs:LangKeys.OpenImageBrowser}}" Style="{StaticResource ButtonPrimary}" HorizontalAlignment="Center"/>
         </StackPanel>
     </hc:TransitioningContentControl>

src/Shared/HandyControlDemo_Shared/UserControl/Controls/ImageBrowserDemoCtl.xaml.cs

@@ -1,10 +1,17 @@
 
+using System;
+
 namespace HandyControlDemo.UserControl;
 
-public partial class ImageBrowserDemoCtl
+public partial class ImageBrowserDemoCtl : IDisposable
 {
     public ImageBrowserDemoCtl()
     {
         InitializeComponent();
     }
+
+    public void Dispose()
+    {
+        ImageViewerDemo.Dispose();
+    }
 }