[cmdpal] Disable clipboard history extension (#40127)

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## Summary of the Pull Request
Base on this discussion:
https://github.com/microsoft/PowerToys/pull/39800

Currently, Flush still have some problem to use it. So, we need to
consider to disbale it.

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Co-authored-by: Yu Leng (from Dev Box) <yuleng@microsoft.com>

src/modules/cmdpal/Microsoft.CmdPal.UI/Microsoft.CmdPal.UI.csproj

@@ -122,7 +122,6 @@
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.Apps\Microsoft.CmdPal.Ext.Apps.csproj" />
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.Bookmark\Microsoft.CmdPal.Ext.Bookmarks.csproj" />
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.Calc\Microsoft.CmdPal.Ext.Calc.csproj" />
-    <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.ClipboardHistory\Microsoft.CmdPal.Ext.ClipboardHistory.csproj" />
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.Registry\Microsoft.CmdPal.Ext.Registry.csproj" />
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.Shell\Microsoft.CmdPal.Ext.Shell.csproj" />
     <ProjectReference Include="..\ext\Microsoft.CmdPal.Ext.TimeDate\Microsoft.CmdPal.Ext.TimeDate.csproj" />