drop async-service dep and copy relevant code into a local async_service

tool, updated for modern handling of ExceptionGroup

tests/core/network/test_notify.py

@@ -10,15 +10,15 @@ features are implemented in swarm
 """
 import enum
 
-from async_service import (
-    background_trio_service,
-)
 import pytest
 import trio
 
 from libp2p.network.notifee_interface import (
     INotifee,
 )
+from libp2p.tools.async_service import (
+    background_trio_service,
+)
 from libp2p.tools.constants import (
     LISTEN_MADDR,
 )