project.restore.configFilePaths differs between Visual Studio and command line

The following appears when running restore on the command line:

```
"project": {
// ...
"restore": {
// ...
"configFilePaths": [
"C:\\dev\\roslyn\\NuGet.config"
],
// ...
```

The following appears when running restore within Visual Studio 2019 RC 3:

```
"project": {
// ...
"restore": {
// ...
"configFilePaths": [
"C:\\dev\\roslyn\\NuGet.Config",
"C:\\Users\\sam\\AppData\\Roaming\\NuGet\\NuGet.Config",
"C:\\Program Files (x86)\\NuGet\\Config\\Microsoft.VisualStudio.Offline.config"
],
// ...
```