fix: keep litellm importable on Python 3.10 and guard 3.11-only typing imports in CI (#39448)

* ci: guard against Python 3.10-incompatible typing imports

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* ci: address Python 3.10 typing guard review

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(ci): honor version-guard direction and scan litellm-proxy-extras in py310 typing check

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

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Co-authored-by: yassin <yassin@berri.ai>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>