Remove old python cmake code

Also don't need to install python3-distutils anymore.

Signed-off-by: Steve Peters <[email protected]>

.github/ci/packages.apt

@@ -2,7 +2,6 @@ libeigen3-dev
 libgz-cmake4-dev
 libgz-utils3-dev
 libpython3-dev
-python3-distutils
 python3-pybind11
 python3-pytest
 ruby-dev

src/python_pybind11/CMakeLists.txt

@@ -73,18 +73,9 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 endif()
 
 if(USE_SYSTEM_PATHS_FOR_PYTHON_INSTALLATION)
-  if(${CMAKE_VERSION} VERSION_LESS "3.12.0")
-    execute_process(
-      COMMAND "${PYTHON_EXECUTABLE}" -c "if True:
-  from distutils import sysconfig as sc
-  print(sc.get_python_lib(plat_specific=True))"
-      OUTPUT_VARIABLE Python3_SITEARCH
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-  else()
-    # Get install variable from Python3 module
-    # Python3_SITEARCH is available from 3.12 on, workaround if needed:
-    find_package(Python3 COMPONENTS Interpreter)
-  endif()
+  # Get install variable from Python3 module
+  # Python3_SITEARCH is available from 3.12 on, workaround if needed:
+  find_package(Python3 COMPONENTS Interpreter)
 
   if(USE_DIST_PACKAGES_FOR_PYTHON)
     string(REPLACE "site-packages" "dist-packages" GZ_PYTHON_INSTALL_PATH ${Python3_SITEARCH})