Further fix dependency conflicts.

- Pin Microsoft.VisualStudio.Validation to correct between VisualStudio.Threading and Microsoft.CodeAnalysis.Remote.Workspaces Microsoft.VisualStudio.Validation conflicts.

eng/Versions.props

@@ -126,6 +126,7 @@
     <MicrosoftVisualStudioTextUIPackageVersion>16.10.8</MicrosoftVisualStudioTextUIPackageVersion>
     <MicrosoftVisualStudioThreadingPackageVersion>16.9.45-alpha</MicrosoftVisualStudioThreadingPackageVersion>
     <MicrosoftVisualStudioWebPackageVersion>16.10.0-preview-1-31008-014</MicrosoftVisualStudioWebPackageVersion>
+    <MicrosoftVisualStudioValidationPackageVersion>16.9.28</MicrosoftVisualStudioValidationPackageVersion>
     <MicrosoftWebToolsLanguagesHtmlPackageVersion>$(Tooling_HtmlEditorPackageVersion)</MicrosoftWebToolsLanguagesHtmlPackageVersion>
     <MicrosoftWebToolsLanguagesLanguageServerServerPackageVersion>$(Tooling_HtmlEditorPackageVersion)</MicrosoftWebToolsLanguagesLanguageServerServerPackageVersion>
     <MicrosoftWebToolsLanguagesSharedPackageVersion>$(Tooling_HtmlEditorPackageVersion)</MicrosoftWebToolsLanguagesSharedPackageVersion>

src/Razor/src/Microsoft.VisualStudio.LiveShare.Razor/Microsoft.VisualStudio.LiveShare.Razor.csproj

@@ -23,6 +23,7 @@
     <PackageReference Include="Microsoft.VisualStudio.LiveShare" Version="$(MicrosoftVisualStudioLiveSharePackageVersion)" />
     <PackageReference Include="Microsoft.VisualStudio.LanguageServices" Version="$(Tooling_MicrosoftVisualStudioLanguageServicesPackageVersion)" />
     <PackageReference Include="Microsoft.VisualStudio.Shell.15.0" Version="$(MicrosoftVisualStudioShell150PackageVersion)" />
+    <PackageReference Include="Microsoft.VisualStudio.Validation" Version="$(MicrosoftVisualStudioValidationPackageVersion)" />
     <PackageReference Include="Newtonsoft.Json" Version="$(VS_NewtonsoftJsonPackageVersion)" />
     <PackageReference Include="System.Collections.Immutable" Version="$(SystemCollectionsImmutablePackageVersion)" />
   </ItemGroup>

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Microsoft.AspNetCore.Razor.Test.Common.csproj

@@ -22,6 +22,7 @@
     <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" Version="$(Tooling_MicrosoftCodeAnalysisWorkspacesCommonPackageVersion)" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="$(MicrosoftExtensionsDependencyModelPackageVersion)" />
     <PackageReference Include="Microsoft.VisualStudio.Threading" Version="$(MicrosoftVisualStudioThreadingPackageVersion)" />
+    <PackageReference Include="Microsoft.VisualStudio.Validation" Version="$(MicrosoftVisualStudioValidationPackageVersion)" />
     <PackageReference Include="xunit.analyzers" Version="$(XunitAnalyzersPackageVersion)" />
     <PackageReference Include="Xunit.Combinatorial" Version="$(XunitCombinatorialPackageVersion)" />
   </ItemGroup>