Use RefOnly prefix to pin ref only versions (dotnet/core-setup#8693)

Commit migrated from https://github.com/dotnet/core-setup/commit/c23328817349489cda3242e3e55fd6b54b2b34a1

src/installer/test/Microsoft.DotNet.CoreSetup.Packaging.Tests/Microsoft.DotNet.CoreSetup.Packaging.Tests.csproj

@@ -11,7 +11,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NuGet.Packaging" Version="$(NugetPackagingPackageVersion)" />
+    <PackageReference Include="NuGet.Packaging" Version="$(RefOnlyNugetPackagingPackageVersion)" />
   </ItemGroup>
 
   <ItemGroup>

tools-local/tasks/core-setup.tasks.csproj

@@ -15,16 +15,16 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="NuGet.ProjectModel" Version="$(NugetProjectModelPackageVersion)" />
+    <PackageReference Include="NuGet.ProjectModel" Version="$(RefOnlyNugetProjectModelPackageVersion)" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="2.1.0" />
     <PackageReference Include="Microsoft.DotNet.PlatformAbstractions" Version="2.1.0" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' != 'net46'">
-    <PackageReference Include="Microsoft.Build" Version="$(MicrosoftBuildPackageVersion)" />
-    <PackageReference Include="Microsoft.Build.Framework" Version="$(MicrosoftBuildFrameworkPackageVersion)" />
-    <PackageReference Include="Microsoft.Build.Tasks.Core" Version="$(MicrosoftBuildTasksCorePackageVersion)" />
-    <PackageReference Include="Microsoft.Build.Utilities.Core" Version="$(MicrosoftBuildUtilitiesCorePackageVersion)" />
+    <PackageReference Include="Microsoft.Build" Version="$(RefOnlyMicrosoftBuildPackageVersion)" />
+    <PackageReference Include="Microsoft.Build.Framework" Version="$(RefOnlyMicrosoftBuildFrameworkPackageVersion)" />
+    <PackageReference Include="Microsoft.Build.Tasks.Core" Version="$(RefOnlyMicrosoftBuildTasksCorePackageVersion)" />
+    <PackageReference Include="Microsoft.Build.Utilities.Core" Version="$(RefOnlyMicrosoftBuildUtilitiesCorePackageVersion)" />
 
     <PackageReference Include="System.Diagnostics.FileVersionInfo" Version="4.0.0" />
   </ItemGroup>