applet: Simplify and fix device change handler in delegate

Actually this code path is not being triggered at all even with ListView.reuseItems because the sort filter model either preserves the delegates or recreates them but not reuses across different devices.

Either way, that status === Component.Ready condition did not make any sense for a statically declared Component, and we should never reset the ListView.currentIndex in delegates if the index is not ours.

Fixes #5 (closed)