setuptools and _distutils_hack symlinks conflict on pip install

[mattem]

If a targets dependencies include the setuptools wheel, then this causes permission denied errors when attempting to install, as site-packages contains readonly symlinks to both setuptools and _distutils_hack.

We should be able to detect this state and not link in these.

 bazel-out/darwin_arm64-fastbuild/bin/ipython.venv.source/bin/python3 -B -s -I -m pip install --quiet --no-compile --require-virtualenv --no-input --no-cache-dir --disable-pip-version-check --no-python-version-warning --only-binary=:all: --no-dependencies --no-index -r bazel-out/darwin_arm64-fastbuild/bin/ipython.venv.requirements.txt
ERROR: Could not install packages due to an OSError: [Errno 13] Permission denied: '/private/var/tmp/_bazel_matt/142bc527510d77fe74ad445c581c00a2/sandbox/darwin-sandbox/10/execroot/rules_py_example/bazel-out/darwin_arm64-fastbuild/bin/ipython.venv.source/lib/python3.8/site-packages/setuptools/__init__.py'
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