patch: remove usage of llm, chat model __call__ (#20788)

- `llm(prompt)` -> `llm.invoke(prompt)`
- `llm(prompt=prompt` -> `llm.invoke(prompt)` (same with `messages=`)
- `llm(prompt, callbacks=callbacks)` -> `llm.invoke(prompt,
config={"callbacks": callbacks})`
- `llm(prompt, **kwargs)` -> `llm.invoke(prompt, **kwargs)`

libs/community/tests/integration_tests/llms/test_baseten.py

@@ -9,5 +9,5 @@ from langchain_community.llms.baseten import Baseten
 def test_baseten_call() -> None:
     """Test valid call to Baseten."""
     llm = Baseten(model=os.environ["BASETEN_MODEL_ID"])
-    output = llm("Test prompt, please respond.")
+    output = llm.invoke("Test prompt, please respond.")
     assert isinstance(output, str)