Python 3.12 deprecated python3-distutils

As for python-3.12 the distutils package has been deprecated.
The latest ax_python_devel.m4 macro from the autoconf archive
has been updated accordingly so let's pull in the new version.

We can also drop the changes made to our customized version
to continue if the development version is not installed since
this functionality has been included upstream.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs#16126

config/always-pyzfs.m4

@@ -80,10 +80,11 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYZFS], [
 			[AC_MSG_ERROR("Python $PYTHON_VERSION unknown")]
 		)
 
-		AX_PYTHON_DEVEL([$PYTHON_REQUIRED_VERSION], [
-			AS_IF([test "x$enable_pyzfs" = xyes], [
-				AC_MSG_ERROR("Python $PYTHON_REQUIRED_VERSION development library is not installed")
-			], [test "x$enable_pyzfs" != xno], [
+		AS_IF([test "x$enable_pyzfs" = xyes], [
+			AX_PYTHON_DEVEL([$PYTHON_REQUIRED_VERSION])
+		], [
+			AX_PYTHON_DEVEL([$PYTHON_REQUIRED_VERSION], [true])
+			AS_IF([test "x$ax_python_devel_found" = xno], [
 				enable_pyzfs=no
 			])
 		])