[S360] Revert "[CmdPal][AOT] Replace CommunityToolkit.MarkdownTextBlock with CommunityToolkit.Lab.MarkdownTextBlock (#39974)" (#40055)

This reverts commit 7d257cf00c due to a
security concern involving multiple feeds

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Directory.Packages.props

@@ -20,7 +20,6 @@
     <PackageVersion Include="CommunityToolkit.WinUI.Extensions" Version="8.2.250402" />
     <PackageVersion Include="CommunityToolkit.WinUI.UI.Controls.DataGrid" Version="7.1.2" />
     <PackageVersion Include="CommunityToolkit.WinUI.UI.Controls.Markdown" Version="7.1.2" />
-    <PackageVersion Include="CommunityToolkit.Labs.WinUI.Controls.MarkdownTextBlock" Version="0.1.250513-build.2126" />
     <PackageVersion Include="ControlzEx" Version="6.0.0" />
     <PackageVersion Include="HelixToolkit" Version="2.24.0" />
     <PackageVersion Include="HelixToolkit.Core.Wpf" Version="2.24.0" />