feat(tool-calling): add tool call passthrough support in LLMRails

Implements tool call extraction and passthrough functionality in LLMRails:
- Add tool_calls_var context variable for storing LLM tool calls
- Refactor llm_call utils to extract and store tool calls from responses
- Support tool calls in both GenerationResponse and dict message formats
- Add ToolMessage support for langchain message conversion
- Comprehensive test coverage for tool calling integration

Author: Pouyanpi

nemoguardrails/actions/llm/utils.py

@@ -226,15 +226,15 @@ def get_colang_history(
                 history += f'user "{event["text"]}"\n'
             elif event["type"] == "UserIntent":
                 if include_texts:
-                    history += f'  {event["intent"]}\n'
+                    history += f"  {event['intent']}\n"
                 else:
-                    history += f'user {event["intent"]}\n'
+                    history += f"user {event['intent']}\n"
             elif event["type"] == "BotIntent":
                 # If we have instructions, we add them before the bot message.
                 # But we only do that for the last bot message.
                 if "instructions" in event and idx == last_bot_intent_idx:
                     history += f"# {event['instructions']}\n"
-                history += f'bot {event["intent"]}\n'
+                history += f"bot {event['intent']}\n"
             elif event["type"] == "StartUtteranceBotAction" and include_texts:
                 history += f'  "{event["script"]}"\n'
             # We skip system actions from this log
@@ -403,9 +403,9 @@ def flow_to_colang(flow: Union[dict, Flow]) -> str:
             if "_type" not in element:
                 raise Exception("bla")
             if element["_type"] == "UserIntent":
-                colang_flow += f'user {element["intent_name"]}\n'
+                colang_flow += f"user {element['intent_name']}\n"
             elif element["_type"] == "run_action" and element["action_name"] == "utter":
-                colang_flow += f'bot {element["action_params"]["value"]}\n'
+                colang_flow += f"bot {element['action_params']['value']}\n"
 
     return colang_flow