Fixing warnings in derivation running

First change to MCTruthClassifier setup fixes a warning that the same tool is added to a tool handle array multiple times.

Second change fixes a warning that the input file metadata doesn't have the currents available, and generates a warning that the geometry and metadata differ in the current they see (which is concerning; I've contacted the sim team about this).

Third change fixes a multiple add warning for the truth collections.

Fourth change guards against adding the same extrapolator multiple times to the ToolSvc.