Update tests/server/request_handlers/test_default_request_handler.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: ishymko

tests/server/request_handlers/test_default_request_handler.py

@@ -1502,7 +1502,7 @@ async def exec_side_effect(_request, queue: EventQueue):
     first_subscribe_event = await anext(resub_gen)
     assert first_subscribe_event == task_for_resub
 
-    received = await resub_gen.__anext__()
+    received = await anext(resub_gen)
     assert received == second_event
 
     # Finish producer to allow cleanup paths to complete