Project paths parsed from Projects

When csproj contains MsBuild Variables in the ProjectReferences they are not properly replaced but just are literally copied.

"ref": "C:\\Source\\\\Tool\\Project\\$(RootDirectory)Tool\\Tool.csproj@undefined",
"dependsOn": []
},

$(RootDirectory) is a Property in the Build

Reproduce the issue with the shown csproj ProjectReferences example, including the $(RootDirectory) MSBuild property. Trace the project-reference path parsing and replacement behavior; done means the generated ref resolves the property instead of retaining the literal variable and an undefined suffix.

Written by the indexing model from the issue text.