Add importlib.util.allowing_all_extensions()

[ericsnowcurrently]

Per PEP 684, we are providing importlib.util.allowing_all_extensions() as a context manager users may use to disable the strict compatablility checks.

I'll be added docs for this separately from the code.

Linked PRs

• gh-104310: Add importlib.util.allowing_all_extensions() #104311
• gh-104310: Rename the New Function in importlib.util #105255
• [3.12] gh-104310: Rename the New Function in importlib.util (gh-105255) #105518

[hauntsaninja]

Thanks!