fix: stores are returned based on if they are checked as active in Settings

Previously on commit df2ac320, stores were introduced as an abstraction on Open Source, PWA and Google Play apps. However, when retrieving these stores, there was no check on the Stores class if the store is marked as selected by the user on the Settings screen.

This fix takes the selection into consideration using AppLoungePreference and only returns those stores which are currently selected.