Suppress pydub warning about ffmpeg/avconv not found (#8940)

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/core/main.py

@@ -5,6 +5,7 @@ from pathlib import Path
 from typing import Callable, Protocol
 
 import openhands.agenthub  # noqa F401 (we import this to get the agents registered)
+import openhands.cli.suppress_warnings  # noqa: F401
 from openhands.controller.agent import Agent
 from openhands.controller.replay import ReplayManager
 from openhands.controller.state.state import State