Avoid explicitly passing the loop to asyncio

This behaviour is deprecated and will be removed in future versions
of Python. Technically, it could be considered a bug (invalid usage
causing different behaviour from the expected one), and in practice
it should not break much code (because .get_event_loop() would likely
be the same event loop anyway).

telethon/tl/custom/conversation.py

@@ -445,8 +445,7 @@ class Conversation(ChatGetter):
         #       cleared when their futures are set to a result.
         return asyncio.wait_for(
             future,
-            timeout=None if due == float('inf') else due - time.time(),
-            loop=self._client.loop
+            timeout=None if due == float('inf') else due - time.time()
         )
 
     def _cancel_all(self, exception=None):