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_llamacpp.py

@@ -35,7 +35,7 @@ def test_llamacpp_inference() -> None:
     """Test valid llama.cpp inference."""
     model_path = get_model()
     llm = LlamaCpp(model_path=model_path)
-    output = llm("Say foo:")
+    output = llm.invoke("Say foo:")
     assert isinstance(output, str)
     assert len(output) > 1
 
@@ -68,7 +68,7 @@ def test_llamacpp_streaming_callback() -> None:
         verbose=True,
         max_tokens=MAX_TOKENS,
     )
-    llm("Q: Can you count to 10? A:'1, ")
+    llm.invoke("Q: Can you count to 10? A:'1, ")
     assert callback_handler.llm_streams <= MAX_TOKENS + OFF_BY_ONE