fix(mypy): properly type valkey conditional import to work in both environments

Author: rodrigo.nogueira

examples/background_tasks.py

@@ -3,14 +3,16 @@
 import asyncio
 from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager, suppress
+from typing import Any
 
+from aiohttp import web
+
+valkey: Any
 try:
-    import valkey.asyncio as valkey  # type: ignore[import-not-found]
+    import valkey.asyncio as valkey  # noqa: E402
 except ImportError:
     valkey = None
 
-from aiohttp import web
-
 valkey_listener = web.AppKey("valkey_listener", asyncio.Task[None])
 websockets = web.AppKey("websockets", list[web.WebSocketResponse])
 skip_valkey_key = web.AppKey("skip_valkey", bool)