fix(lint): remove unreachable None check in _resolve_fine_tuning_timeout

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

litellm/fine_tuning/main.py

@@ -131,13 +131,11 @@ def _resolve_fine_tuning_timeout(
     custom_llm_provider: str,
 ) -> float:
     """Normalise a raw timeout value to a float (seconds) for fine-tuning calls."""
-    timeout = timeout or 600
+    timeout = timeout or 600.0
     if isinstance(timeout, httpx.Timeout):
         if not supports_httpx_timeout(custom_llm_provider):
             return float(timeout.read or 600)
         return timeout  # type: ignore[return-value]
-    if timeout is None:
-        return 600.0
     return float(timeout)