cmake: use if(IN_LIST) where possible

CMakeLists.txt

@@ -249,8 +249,7 @@ if (vtk_required_modules OR vtk_unrecognized_modules)
     "${vtk_required_modules};${vtk_unrecognized_modules}.")
 endif ()
 
-list(FIND vtk_modules "VTK::Python" vtk_python_idx)
-if (NOT vtk_python_idx EQUAL "-1")
+if ("VTK::Python" IN_LIST vtk_modules)
   include(vtkModuleWrapPython)
   vtk_module_python_default_destination(VTK_PYTHON_SITE_PACKAGES_SUFFIX)
 endif ()