Fix llms.Mlflow example (#14386)

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The example code for `llms.Mlflow` is outdated.

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

libs/community/langchain_community/llms/mlflow.py

@@ -33,7 +33,7 @@ class Mlflow(LLM):
             completions = Mlflow(
                 target_uri="http://localhost:5000",
                 endpoint="test",
-                params={"temperature": 0.1}
+                temperature=0.1,
             )
     """