.Net: Enable package validation for the liquid prompt template package (microsoft#11818)

Contributes to:
microsoft#10070

Author: SergeyMenshykh

dotnet/src/Extensions/PromptTemplates.Liquid/PromptTemplates.Liquid.csproj

@@ -6,7 +6,7 @@
     <RootNamespace>$(AssemblyName)</RootNamespace>
     <TargetFrameworks>net8.0;netstandard2.0</TargetFrameworks>
     <NoWarn>$(NoWarn)</NoWarn>
-    <EnablePackageValidation>false</EnablePackageValidation>
+    <EnablePackageValidation>true</EnablePackageValidation>
   </PropertyGroup>
 
   <Import Project="$(RepoRoot)/dotnet/nuget/nuget-package.props" />