Do not save to cache file at unload when cache is disabled

Author: brefra

plugwise_usb/nodes/__init__.py

@@ -604,6 +604,8 @@ async def get_state(
 
     async def unload(self) -> None:
         """Deactivate and unload node features."""
+        if not self._cache_enabled:
+            return
         if self._cache_save_task is not None and not self._cache_save_task.done():
             await self._cache_save_task
         await self.save_cache(trigger_only=False, full_write=True)