hide unable to resolve host exceptions when there are more videos in a playlist

This is in response to playing a downloaded playlist while offline.

If not all content has been downloaded (spotify songs as part of the playlist won't be downloaded) there are two issues:

1. The playback tracker fails to function because of a network error displaying an exception dialog
2. The video fails to load because of the network error displaying an exception dialog

The first change turns a playback tracker exception dialog into a simple toast notification if the error is network related