chore: Update Avalonia to 0.10.21 (#5124)

Directory.Packages.props

@@ -3,11 +3,11 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
   </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="Avalonia" Version="0.10.19" />
-    <PackageVersion Include="Avalonia.Controls.DataGrid" Version="0.10.19" />
-    <PackageVersion Include="Avalonia.Desktop" Version="0.10.19" />
-    <PackageVersion Include="Avalonia.Diagnostics" Version="0.10.19" />
-    <PackageVersion Include="Avalonia.Markup.Xaml.Loader" Version="0.10.19" />
+    <PackageVersion Include="Avalonia" Version="0.10.21" />
+    <PackageVersion Include="Avalonia.Controls.DataGrid" Version="0.10.21" />
+    <PackageVersion Include="Avalonia.Desktop" Version="0.10.21" />
+    <PackageVersion Include="Avalonia.Diagnostics" Version="0.10.21" />
+    <PackageVersion Include="Avalonia.Markup.Xaml.Loader" Version="0.10.21" />
     <PackageVersion Include="Avalonia.Svg" Version="0.10.18" />
     <PackageVersion Include="Avalonia.Svg.Skia" Version="0.10.18" />
     <PackageVersion Include="CommandLineParser" Version="2.9.1" />