[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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NOTICE.md

@@ -1497,7 +1497,6 @@ SOFTWARE.
 - Appium.WebDriver 4.4.5
 - Azure.AI.OpenAI 1.0.0-beta.17
 - CommunityToolkit.Common 8.4.0
-- CommunityToolkit.Labs.WinUI.Controls.MarkdownTextBlock 0.1.250513-build.2126
 - CommunityToolkit.Mvvm 8.4.0
 - CommunityToolkit.WinUI.Animations 8.2.250402
 - CommunityToolkit.WinUI.Collections 8.2.250402