`dotnet pack` fails on Roslyn.slnx

Repro:
1) Checkout `main` in a clean enlistment
2) run `dotnet pack -bl -c Debug Roslyn.slnx`

The build fails with two errors:

```
Restore complete (6.7s)
Microsoft.CodeAnalysis.PooledObjects.Package netstandard2.0 succeeded (6.9s) → artifacts\bin\Microsoft.CodeAnalysis.PooledObjects.Package\Debug\netstandard2.0\Microsoft.CodeAnalysis.PooledObjects.Package.dll
Microsoft.VisualStudio.Extensibility.Testing.Xunit net472 failed with 1 error(s) (0.1s)
C:\Program Files\dotnet\sdk\10.0.102\NuGet.Build.Tasks.Pack.targets(222,5): error NU5026: The file 'E:\R3\artifacts\bin\Microsoft.VisualStudio.Extensibility.Testing.Xunit\Debug\net472\Microsoft.VisualStudio.Extensibility.Testing.Xunit.dll' to be packed was not found on disk.
```

```
GenerateAnalyzerNuspec net10.0 failed with 1 error(s) (0.0s)
C:\Program Files\dotnet\sdk\10.0.102\NuGet.RestoreEx.targets(19,5): error An error occurred starting static graph-based restore. An error occurred trying to start process 'C:\Program Files\dotnet\dotnet' with working directory 'E:\R3\src\RoslynAnalyzers\Tools\GenerateAnalyzerNuspec'. The filename or extension is too long.. Please file an issue at https://github.com/NuGet/Home
```

Filed https://github.com/NuGet/Home/issues/14731 for the second issue.

Binlog available on internal share:
https://onedrive.cloud.microsoft/:u:/a@ke39vq9p/S/IQDF9zt9bbpoRLroPq8pZVHjAQMj5nbJQhiFHXuXBhyxDf8?e=RIt7CH