When adding/deleting external actions, the UI would sometimes show
duplicated or cloned rows due to a race condition between:
1. The optimistic setActions() call updating local state
2. The save() callback updating externalActions in context
3. The useEffect syncing actions from externalActions
This fix removes the optimistic updates and lets the server response
be the single source of truth, updating the UI only after the context
is updated via the save() success callback.
Fixes#4347
