ProcessTerminationTimeout is null for 2.0.0

```cs
using System.CommandLine;

var invokeConfig = new InvocationConfiguration()
{
EnableDefaultExceptionHandler = true
};

Console.WriteLine($"ProcessTerminationTimeout: {invokeConfig.ProcessTerminationTimeout?.ToString() ?? "(null)"}");
Console.ReadKey();
```

Result:

I'm confused because it is included in the release/10.0 branch: https://github.com/dotnet/command-line-api/pull/2674/files and https://github.com/dotnet/command-line-api/blob/release/10.0/src/System.CommandLine/InvocationConfiguration.cs#L21