Moved system_python dep into upb_deps().

WORKSPACE

@@ -3,7 +3,6 @@ workspace(name = "upb")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("//bazel:python_downloads.bzl", "python_source_archive", "python_nuget_package")
 load("//bazel:workspace_deps.bzl", "upb_deps")
-load("//bazel:system_python.bzl", "system_python")
 
 upb_deps()
 
@@ -43,12 +42,6 @@ http_archive(
     patch_cmds = ["find google -type f -name BUILD.bazel -delete"],
 )
 
-system_python(
-    name = "system_python"
-)
-
-register_toolchains("@system_python//:python_toolchain")
-
 http_archive(
     name = "rules_fuzzing",
     sha256 = "23bb074064c6f488d12044934ab1b0631e8e6898d5cf2f6bde087adb01111573",

bazel/workspace_deps.bzl

@@ -1,6 +1,7 @@
 load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("//bazel:workspace_defs.bzl", "system_python")
 
 def upb_deps():
     maybe(
@@ -42,3 +43,9 @@ def upb_deps():
         strip_prefix = "bazel-skylib-main",
         urls = ["https://github.com/bazelbuild/bazel-skylib/archive/main.tar.gz"],
     )
+
+    system_python(
+        name = "system_python"
+    )
+
+    native.register_toolchains("@system_python//:python_toolchain")