.tar.gz files not being correctly repacked with SignTool in .NET 8.0

[ellahathaway]

It was revealed today that .tar.gz files are not being correctly repacked when signing with SignTool in .NET 8.0.

Here are examples of builds:

• Build with correct .tar.gz (no runpacking/repacking of .tar.gz with SignTool)
• Build with incorrect .tar.gz (unpacking/repacking of .tar.gz with SignTool)

Looking through the binlogs, it appears that the files get extracted correctly from the containers, but it is unclear why they do not get properly repacked.

We should investigate this, as this could negatively impact signing for repos who attempt to use the tooling for these files.

cc @tmat - Including you on this since I believe you wrote the unpacking/repacking tar infra that SignTool uses for these files. For context, I enabled the unpacking of .tar.gz files using the tooling you wrote with this 8.0 PR