feat: add AccountsChanged and AccountsItemChanged events (#6118)

- **feat: add `AccountsChanged` and `AccountsItemChanged` events**
- **emit event and add tests**

closes #6106

TODO:
- [x] test receiving synced config from second device
- [x] bug: investigate how to delay the configuration event until it is
actually configured - because desktop gets the event but still shows
account as if it was unconfigured, maybe event is emitted before the
value is written to the database?
- [x] update node bindings constants

src/imex.rs

@@ -426,6 +426,7 @@ async fn import_backup_stream_inner<R: tokio::io::AsyncRead + Unpin>(
     if res.is_ok() {
         context.emit_event(EventType::ImexProgress(999));
         res = context.sql.run_migrations(context).await;
+        context.emit_event(EventType::AccountsItemChanged);
     }
     if res.is_ok() {
         delete_and_reset_all_device_msgs(context)