feat: explicitly load rules_python in config_system BUILD.bazel

In config_system/BUILD.bazel we explicitly load py_binary and py_binary using rules_python. In Bazel 9.0, the --incompatible_autoload_externally flag is empty by default, which means all rulesets have to be explicitly loaded from external modules.

Change-Id: Ib9184dbc7e7ae1ff9dc64bb30c9a3743082d1359
Signed-off-by: Nial Daly <nial.daly@arm.com>

Author: nialdaly

config_system/BUILD.bazel

@@ -1,5 +1,7 @@
 load("@bazel_skylib//rules:native_binary.bzl", "native_binary")
 load("@config_deps//:requirements.bzl", "requirement")
+load("@rules_python//python:py_binary.bzl", "py_binary")
+load("@rules_python//python:py_library.bzl", "py_library")
 
 exports_files(
     srcs = ["pytest.ini"],