Throw Command Unknown for dependency tools in libraries. (#2933)

* Throw Command Unknown for dependency tools in libraries.

* Add testProjects to test tools command for libraries.

* update failing tests

* Add tests verifying that dependency tools are not available in libraries

TestAssets/DesktopTestProjects/LibraryWithDirectDependencyDesktopAndPortable/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("Hello World!");
+        }
+    }
+}