Remove pack references

[lewing]

No description provided.

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[lewing]

errors and so far are nuget restore errors

 Check failure on line 19 in .dotnet/sdk/6.0.100-preview.4.21255.9/NuGet.RestoreEx.targets 

@azure-pipelinesazure-pipelines
/ dotnet-linker-tests (Build Linux x64 release Runtime_Release)
.dotnet/sdk/6.0.100-preview.4.21255.9/NuGet.RestoreEx.targets#L19
.dotnet/sdk/6.0.100-preview.4.21255.9/NuGet.RestoreEx.targets(19,5): error : (NETCORE_ENGINEERING_TELEMETRY=Restore) Failed to retrieve information about 'Microsoft.NETCore.App.Ref' from remote source 'https://pkgs.dev.azure.com/dnceng/9ee6d478-d288-47f7-aacc-f6e6d082ae6d/_packaging/c9f8ac11-6bd8-4926-8306-f075241547f7/nuget/v3/flat2/microsoft.netcore.app.ref/index.json'.
   at NuGet.Protocol.HttpFileSystemBasedFindPackageByIdResource.FindPackagesByIdAsync(String id, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Protocol.dll:token 0x6000393+0x354
   at NuGet.Protocol.HttpFileSystemBasedFindPackageByIdResource.EnsurePackagesAsync(String id, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Protocol.dll:token 0x6000392+0x13f
   at NuGet.Protocol.HttpFileSystemBasedFindPackageByIdResource.DoesPackageExistAsync(String id, NuGetVersion version, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Protocol.dll:token 0x6000391+0x17c
   at NuGet.Commands.SourceRepositoryDependencyProvider.FindLibraryCoreAsync(LibraryRange libraryRange, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Commands.dll:token 0x600045b+0x379
   at NuGet.Protocol.HttpFileSystemBasedFindPackageByIdResource.DoesPackageExistAsync(String id, NuGetVersion version, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Protocol.dll:token 0x6000391+0x17c
   at NuGet.Commands.SourceRepositoryDependencyProvider.FindLibraryAsync(LibraryRange libraryRange, NuGetFramework targetFramework, SourceCacheContext cacheContext, ILogger logger, CancellationToken cancellationToken) in NuGet.Commands.dll:token 0x600045a+0x1a7
   at NuGet.DependencyResolver.ResolverUtility.<>c__DisplayClass9_1.<<FindLibraryFromSourcesAsync>b__0>d.MoveNext() in NuGet.DependencyResolver.Core.dll:token 0x600013f+0xd2
--- End of stack trace from previous location ---