[Logs UI] Enable loading and saving of unified search queries

[weltenwort]

📓 Summary

We want to support the "saved query" feature of the unified search bar in the Logs UI. To enable this we want to extend the LogStreamQuery state machine with the ability to interact with the saved query service.

• 🔗 depends on [Logs UI] Refactor log stream page time state #145137
• 🔗 depends on [Logs UI] Add log stream page filter state and UI #142764

✔️ Acceptance criteria

• The LogStreamQuery state machine can load a saved query on initialization.
• The loaded saved query id is persisted in the URL.
• The page state stays consistent in the sense that no incorrect query or filters are applied while loading the saved query is in progress.
• The query, filter and time state in the url overrides the query, filter and time retrieved from the saved query.
• The loaded saved query can be updated with new query, filter and time state via the unified search bar menu.

[elasticmachine]

Pinging @elastic/infra-monitoring-ui (Team:Infra Monitoring UI)

[weltenwort]

@Kerry350 I'd appreciate your feedback on the ACs before we call this "ready"

[Kerry350]

@weltenwort They look good to me, except maybe:

(Optional) The query and filter state in the url is only set when either differs from the saved query state.

We might want to discuss this one as it has ramifications for when we reload the page again and we then have the discrepancy over precedence.

[weltenwort]

Good point! Maybe we should replace this with a point that clarifies the precedence instead.

[smith]

We're not planning on completing this at this time.