Visible delay between app UI and web view when switching reading modes about swift-toolkit

At first glance, this might be related to the new user settings injection implementation.

[mickael-menu-mantano]

I'm closing this issue as it is quite old and I couldn't reproduce it on the simulator nor my devices. Feel free to reopen if needed.

There is a slight delay but it's far from being like in Jiminy's GIF, and it's to be expected since the theme application is asynchronous. I think the API could benefit from a completion closure called when the theme is applied in the navigator, so that the app can update its own interface afterwards. But it's probably not worth adding that now since a refactoring of the user settings is coming once the public API will be specified.