Remove unnecessary explicit use of OrderedDict in nest media source (#61054)

Address follow up PR comments from #60073

homeassistant/components/nest/media_source.py

@@ -18,7 +18,6 @@ https://developers.google.com/nest/device-access/api/camera#handle_camera_events
 
 from __future__ import annotations
 
-from collections import OrderedDict
 from collections.abc import Mapping
 from dataclasses import dataclass
 import logging
@@ -204,7 +203,7 @@ class NestMediaSource(MediaSource):
 async def _get_events(device: Device) -> Mapping[str, ImageEventBase]:
     """Return relevant events for the specified device."""
     events = await device.event_media_manager.async_events()
-    return OrderedDict({e.event_id: e for e in events})
+    return {e.event_id: e for e in events}
 
 
 def _browse_root() -> BrowseMediaSource: