Improve typing for Lite

[awaelchli]

What does this PR do?

Follow up to #10682
#10682 will remove Lite from mypy checked typing, but we need to keep it there.

Part of #7037

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Did you have fun?

I made sure I had fun coding 🙃

Part of #1 (it's a lie, this is just here to avoid noisy GitHub bot)

cc @Borda @carmocca @justusschock @awaelchli

[tchaton]

LGTM !