[gui] mini-search sometimes does not populate

[dskvr]

I think it is a race condition, it seems to only happen in very specific circumstances.

It is perplexing because the minisearch index is subscribed to a store that is populated when this issue occurs. INterestingly, when there is a worker-relay failure and the events store is only populated with relays from single relay page fetches, this never happens.

Possibly related to #708