Avoid reconstructing the Dispatch object

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/dispatch/_bg_service.py

@@ -280,7 +280,7 @@ async def _fetch(self) -> None:
                 for client_dispatch in page:
                     dispatch = Dispatch(client_dispatch)
 
-                    self._dispatches[dispatch.id] = Dispatch(client_dispatch)
+                    self._dispatches[dispatch.id] = dispatch
                     old_dispatch = old_dispatches.pop(dispatch.id, None)
                     if not old_dispatch:
                         _logger.debug("New dispatch: %s", dispatch)