ProjectService is incorrectly initialized in agents

[CharliePoole]

I noticed this when examining all the services needed by an agent, hoping to build a version of the agent that doesn't depend on the engine itself.

In Program.cs we create and initialize the ProjectService for the engine. That service

1. Is not intended to exist in the agent, because all projects are supposed to have been resolved before the agent is called and passed a TestPackage.

2. Is never otherwise referenced in the engine.

While initializing it does no harm, it's confusing and makes it difficult to simplify the agent. There's also a risk that someone will start using it, perhaps re-expanding projects that are already expanded once.