rename socket.py to listen_socket.py to avoid circular import

[diwu-sf]

Running python openhands/server/listen.py will show this import error, due to socket.py naming conflict:

Traceback (most recent call last):
  File "OpenHands/openhands/server/listen.py", line 1, in <module>
    import socketio
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/socketio/__init__.py", line 1, in <module>
    from .client import Client
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/socketio/client.py", line 3, in <module>
    import engineio
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/engineio/__init__.py", line 1, in <module>
    from .client import Client
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/engineio/client.py", line 5, in <module>
    import ssl
  File "miniconda3/lib/python3.12/ssl.py", line 260, in <module>
    from socket import socket, SOCK_STREAM, create_connection
  File "OpenHands/openhands/server/socket.py", line 1, in <module>
    from fastapi import status
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/fastapi/__init__.py", line 7, in <module>
    from .applications import FastAPI as FastAPI
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/fastapi/applications.py", line 16, in <module>
    from fastapi import routing
  File "openhands-ai-uMz2TtsD-py3.12/lib/python3.12/site-packages/fastapi/routing.py", line 1, in <module>
    import asyncio
  File "miniconda3/lib/python3.12/asyncio/__init__.py", line 8, in <module>
    from .base_events import *
  File "miniconda3/lib/python3.12/asyncio/base_events.py", line 41, in <module>
    from . import events
  File "miniconda3/lib/python3.12/asyncio/events.py", line 211, in <module>
    class AbstractEventLoop:
  File "miniconda3/lib/python3.12/asyncio/events.py", line 320, in AbstractEventLoop
    *, family=socket.AF_UNSPEC,
              ^^^^^^^^^^^^^^^^
AttributeError: partially initialized module 'socket' has no attribute 'AF_UNSPEC' (most likely due to a circular import)