Fixes MAGN-4817 Simplified conversion to a Revit Arc

This PR changes the conversion method from a ProtoGeometry Arc to a Revit arc, using a three point constructor rather than a plane-based constructor. Creating the required information for a plane-based constructor was buggy.

@pboyer / @ikeough / @Randy-Ma PTAL


@hlp 

Could you help add a test case for this?