Use same logic for playback stop events and offline listen log

[Maxr1998]

The boolean expression we currently use for server stop events already works very well, so the same should be used while offline (in the onTrackChanged callback). I also added a logging call to the OfflineListenLogHelper for good measure.

[Chaphasilor]

Thanks, will take a look tomorrow!

One thing I thought about today, will the currently playing track be properly logged when going offline mid-playback? Probably yes, since it only logs when it ends (since your recent PR), right?

[Maxr1998]

Yup, it should, since the check is indeed at the end. I think I even tested this once.
The same applies in the reverse case too, once you go back online the usual logging is used again (and should work, since Jellyfin won't enforce a matching start event iirc).

[Chaphasilor]

Awesome, thanks!