fix: make bazel 9 workspace recognize rules_python as the main module

[rickeylev]

Building with Bazel 9 using WORKSPACE results in an odd error that PyInfo
isn't defined. Oddly, the error refers to rules_python/python/private/reexports.bzl
for rules_python 0.28.0. This seems to only happen when the main module is rules_python.

While Bazel 9 is supposed to drop workspace support, I've been advised it's better to
keep testing WORKSPACE support until closer to when Bazel 9 fully removes it.

My best guess about what's happening is Bazel's autoloading is triggering and somehow
defining rules_python before it's recognized that the main module is rules_python.
The autoloading appears to be triggered, eventually, by things in bazel_tools loading
rules_python.

While removing unnecessary @bazel_tools loads in rules_python helps, the particular
case I can't find a clean solution to is when
@@rules_java//toolchains:toolchain_java11_definition causes rules_python to be
loaded. This appears to end up loading rules_python via
@bazel_tools//tools/jdk:BUILD, which has has some py rules defined in it.

To fix/work around this issue, local_repository can be used to define the rules_python
repo before autoloading happens. This appears to take precedence over whatever logic
autoloading has.

Work towards #2469