[Packaging] Fix #24788: Add -I in entrypoint on MacOS

[bebound]

Description

Fix #24788.

az start with python -m and -m adds the current directory to the start of sys.path.

In #24788, if the working dir has a brotli folder, urllib3 will import it and lead to error.
https://github.com/urllib3/urllib3/blob/0612a53f48f72ab6e9ef58ccf1d6a25b847152fc/src/urllib3/response.py#L17-L23

To remove current dir from path, -I is needed.

-I option can be used to run the script in isolated mode where sys.path contains neither the current directory nor the user’s site-packages directory. All PYTHON* environment variables are ignored, too. ----Python doc

-I has already been added in entrypoint on Linux and Windows, this PR adds it on MacOS.

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[yonzhan]

Packaging

[jiasli]

I happen to have a PR to refine the help message for -I 😆 :

• Doc: Add "the current working directory" to -I's description  python/cpython#100526

[jiasli]

Very clear PR description!