pqSMTKResourceRepresentation: cast to common base class

Recently, SMTK switched from using vtkPVCompositeRepresentation to
using vtkSMTKCompositeRepresentation. Both classes inherit from
vtkCompositeRepresentation. This update fixes a cast to refer to the
base class that is common to both, so the subsequent call to the
active representation will succeed.
Status Job ID Name Coverage
  External
passed cdash

passed ghostflow-branch-check-master

failed smtk@master-kerbin-windows-shared-release+examples+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+private+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+python3+remus+vtk

pending smtk@master-moho-linux-shared-relwithdebinfo+examples+remus
failed smtk@master-moho-linux-shared-relwithdebinfo+examples+remus+vtk

failed smtk@master-norkit-osx-shared-release+examples+matplotlib

running smtk@master-praxis-windows-shared-release

2098:23:27

failed smtk@master-talosiv-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib+private

passed cdash

failed smtk@master-kerbin-windows-shared-release+examples+remus

00:01:50

failed smtk@master-kerbin-windows-shared-release+examples+remus

failed smtk@master-kerbin-windows-shared-release+examples+remus

failed smtk@master-kerbin-windows-shared-release+examples+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+private+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+private+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+private+remus

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+private+remus

00:03:23

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+python3+remus+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+python3+remus+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+python3+remus+vtk

00:00:06

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+python3+remus+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+remus+vtk

00:03:24

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+remus+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+remus+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+examples+remus+vtk

failed smtk@master-norkit-osx-shared-release+examples+matplotlib

failed smtk@master-norkit-osx-shared-release+examples+matplotlib

00:00:10

failed smtk@master-norkit-osx-shared-release+examples+matplotlib

failed smtk@master-norkit-osx-shared-release+examples+matplotlib

failed smtk@master-talosiv-osx-shared-release+examples+matplotlib

failed smtk@master-talosiv-osx-shared-release+examples+matplotlib

00:07:05

failed smtk@master-talosiv-osx-shared-release+examples+matplotlib

failed smtk@master-talosiv-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib

00:01:55

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib+private

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib+private

00:02:21

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib+private

failed smtk@master-tatooine-osx-shared-release+examples+matplotlib+private