Replace clear_connect_callbacks with _deregister_connect_callback (#2955)

Author: dvora-h

redis/asyncio/client.py

@@ -783,7 +783,7 @@ async def __aexit__(self, exc_type, exc_value, traceback):
 
     def __del__(self):
         if self.connection:
-            self.connection.clear_connect_callbacks()
+            self.connection._deregister_connect_callback(self.on_connect)
 
     async def aclose(self):
         # In case a connection property does not yet exist