Add `Checker::import_from_typing` (#17340)
Summary
--
This PR replaces uses of version-dependent imports from `typing` or
`typing_extensions` with a centralized `Checker::import_from_typing`
method.
The idea here is to make the fix for #9761 (whatever it ends up being)
applicable to all of the rules performing similar checks.
Test Plan
--
Existing tests for the affected rules.
