condition the PackTool targets so that only tool packages get the changes inside them to prevent unintentional modifications

Author: baronfel

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets

@@ -1432,7 +1432,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.ObsoleteReferences.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Publish.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PackStubs.targets" Condition="('$(Language)' == 'C++' and '$(_EnablePackageReferencesInVCProjects)' != 'true')"/>
-  <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PackTool.targets" />
+  <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PackTool.targets" Condition="'$(PackAsTool)' == 'true'" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PackProjectTool.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PreserveCompilationContext.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.ConflictResolution.targets" />