The env vars in the regression tests had no effect — the functions under
test operate only on the params dict and don't read from env vars.
Clean up the test setup to avoid misleading future maintainers.
Greptile feedback: P2
TypedDict does not support attribute access (config.attr), must use
dict-style access (config['key']). Fix the regression test that was
failing after the None-guard fix was applied.
Fix AttributeError: 'NoneType' object has no attribute 'get' when Langfuse
is configured via environment variables (no per-request dynamic params).
In _dynamic_langfuse_credentials_are_passed() and
get_dynamic_langfuse_logging_config(), standard_callback_dynamic_params can
be None (not {}). Calling .get() directly on None raises AttributeError.
Fix: use params = standard_callback_dynamic_params or {} before calling .get().
Added regression tests for both functions to ensure None is handled correctly.
Fixes: BerriAI/litellm#25940
