Add redirections for distribution level pages because they're removed…

[junshi356]

… for simplifying TOC

[learn-build-service-prod]

Learn Build status updates of commit c3eec71:

✅ Validation status: passed

File	Status	Preview URL	Details
.openpublishing.publish.config.json	✅Succeeded
redirections/.openpublishing.redirection.simplify-package-structure.json	✅Succeeded	View (msal-py-latest)

For more details, please refer to the build report.

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[junshi356]

Python converter is removing distribution level pages.
https://learn.microsoft.com/en-us/python/api/msal will be removed
We will redirect it to:
https://learn.microsoft.com/en-us/python/api/msal/msal

The redirection is working on review site:
https://review.learn.microsoft.com/en-us/python/api/msal?branch=pr-en-us-80