COMP: Build itkPyCommand.cxx against Python3::SABIModule

The Python3::Module fallback was reachable only without the limited API.
A missing SABIModule target is now an explicit configure error rather
than a silent downgrade.

Author: hjmjohnson

Modules/Core/Common/src/CMakeLists.txt

@@ -162,17 +162,19 @@ set(
 )
 
 if(ITK_WRAP_PYTHON)
-  if(ITK_USE_PYTHON_LIMITED_API AND TARGET Python3::SABIModule)
-    set(_itk_python_target Python3::SABIModule)
-  else()
-    set(_itk_python_target Python3::Module)
+  if(NOT TARGET Python3::SABIModule)
+    message(
+      FATAL_ERROR
+      "ITK_WRAP_PYTHON=ON requires the Python3 Development.SABIModule component, "
+      "but the Python3::SABIModule target was not defined."
+    )
   endif()
   list(APPEND ITKCommon_SRCS itkPyCommand.cxx)
   set_source_files_properties(
     itkPyCommand.cxx
     PROPERTIES
       INCLUDE_DIRECTORIES
-        "$<TARGET_PROPERTY:${_itk_python_target},INTERFACE_INCLUDE_DIRECTORIES>"
+        "$<TARGET_PROPERTY:Python3::SABIModule,INTERFACE_INCLUDE_DIRECTORIES>"
   )
 endif()