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/langchain_community/llms/gpt4all.py

@@ -21,7 +21,7 @@ class GPT4All(LLM):
             model = GPT4All(model="./models/gpt4all-model.bin", n_threads=8)
 
             # Simplest invocation
-            response = model("Once upon a time, ")
+            response = model.invoke("Once upon a time, ")
     """
 
     model: str
@@ -197,7 +197,7 @@ class GPT4All(LLM):
             .. code-block:: python
 
                 prompt = "Once upon a time, "
-                response = model(prompt, n_predict=55)
+                response = model.invoke(prompt, n_predict=55)
         """
         text_callback = None
         if run_manager: