Prefer csproj method for InternalsVisibleTo

https://learn.microsoft.com/en-us/dotnet/core/project-sdk/msbuild-props#internalsvisibleto

This way, you can skip the AssemblyInfo.cs creation.

Also, [this](https://www.meziantou.net/declaring-internalsvisibleto-in-the-csproj.htm) might work:

```

net6.0

```

Read the linked MSBuild InternalsVisibleTo documentation and inspect the repository's .csproj and AssemblyInfo.cs files. Confirm how tests currently access internals, then verify that the project configuration provides the same access without creating AssemblyInfo.cs and that the test suite still passes.

Written by the indexing model from the issue text.