Blocking UI while while loading is in progress since navigating from this view controller during Jetpack connection or disconnection process can leave the application in an undetermined state.

Previously the blog was made not visible after disconnecting, however that leaves the app in the undetermined state until refresh happens

When all the blogs are removed, split screen details view should not have any view controllers set

In a case when the blog is removed when Jetpack view is opened, we don't need to reload the view if the blog no longer exists

…r.swift

Co-authored-by: Salim <salim.braksa@automattic.com>