[Woo POS] Avoid triggering dashboard view redraws whenever any POS aggregate model property changes

[jaclync]

For issues #14853 and #14860, whenever PointOfSaleAggregateModel.itemsViewState is updated like for the loading state while waiting for the API request, the refresh control async task refreshable gets canceled because the top-level view PointOfSaleDashboardView is redrawn (and thus the ItemListView).

There are workarounds to preserve the async task for refreshable, but with tradeoffs. Ideally, we can avoid triggering redraws by providing more granular updates instead of the whole ObservableObject PointOfSaleAggregateModel being changed. The best candidate so far is iOS 17+ Observation framework. Some refactoring is likely required.

[dangermattic]

Thanks for reporting! 👍

[malinajirka]

@jaclync I'm trying to understand the priority of this issue. What is the impact of this behavior?

[jaclync]

The impact would be to resolve a tech debt where we put a workaround in #14870 (diffs in the refreshable) so that the pull-to-refresh async task isn't canceled from unintended redraws due to other state changes in the POS aggregate model.

One potential solution is to use the iOS 17+ Observation framework so that other state changes only trigger redraws for the affected views, not the refresh control. From pdfdoF-6lP-p2#comment-7478, @joshheald is working on it this week. The granular UI updates from state changes could also bring other benefits such as performance since it no longer triggers redraws for the whole view. The main risks are the increase of minimum iOS version, and a potentially significant amount of changes to the POS code.