chore: style cleanup re-raising a bare exception

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: allenporter

roborock/devices/device_manager.py

@@ -78,7 +78,7 @@ async def discover_devices(self, prefer_cache: bool = True) -> list[RoborockDevi
                 cache_data.home_data = await self._web_api.get_home_data()
             except RoborockException as ex:
                 if not cache_data.home_data:
-                    raise ex
+                    raise
                 _LOGGER.debug("Failed to fetch home data, using cached data: %s", ex)
             await self._cache.set(cache_data)
         home_data = cache_data.home_data