refactor: remove model parameter from AIAgent initialization

Eliminated the model parameter from the AIAgent class initialization, streamlining the constructor and ensuring consistent behavior across agent instances. This change aligns with recent updates to the task delegation logic.

run_agent.py

@@ -2619,7 +2619,6 @@ class AIAgent:
                         context=function_args.get("context"),
                         toolsets=function_args.get("toolsets"),
                         tasks=tasks_arg,
-                        model=function_args.get("model"),
                         max_iterations=function_args.get("max_iterations"),
                         parent_agent=self,
                     )