COMP: Update Python header and include path

Set include directories for Python wrapping from Python3::Module
target.

Changed Python header inclusion to use angle brackets for consistency.
Added include directory properties for `itkPyCommand.cxx` to improve
Python wrapping configuration.

Author: hjmjohnson

Modules/Core/Common/include/itkPyCommand.h

@@ -24,7 +24,7 @@
 // The python header defines _POSIX_C_SOURCE without a preceding #undef
 #undef _POSIX_C_SOURCE
 #undef _XOPEN_SOURCE
-#include "Python.h"
+#include <Python.h>
 
 namespace itk
 {

Modules/Core/Common/src/CMakeLists.txt

@@ -160,6 +160,12 @@ set(
 
 if(ITK_WRAP_PYTHON)
   list(APPEND ITKCommon_SRCS itkPyCommand.cxx)
+  set_source_files_properties(
+    itkPyCommand.cxx
+    PROPERTIES
+      INCLUDE_DIRECTORIES
+        "$<TARGET_PROPERTY:Python3::Module,INTERFACE_INCLUDE_DIRECTORIES>"
+  )
 endif()
 
 if(WIN32)