Azure function project doesn't copy system.private.servicemodel.dll to the output directory

This is the same issue with #3568. That issue is closed but we still need to manually modify the csproj file to make it copy the dll. This doesn't seem fixed at all.

Start by comparing this report with issue #3568 and inspect the Azure Function project's .csproj handling for System.Private.ServiceModel.dll. Reproduce the build or publish output and verify whether the DLL is copied without manually modifying the project file. Done means the reported output-directory behavior is fixed and confirmed by a regression check.

Written by the indexing model from the issue text.