"Manage Playlists" and "Default playlist": Improve UX

[fredsleeve]

You can have only one default playlist, but maybe not everyone knows that at a first glance.

So if you try to remove the "default playlist" option via "Manage playlists" and click ok, the option wouldn't change until you set another playlist as default.

I would expect that the app tells you that or the option is visible but disabled if you are in the edit mode of a playlist which is set as a "default playlist".

[gemiren]

You can remove the default playlist if there is at least one more playlist. The app will then use the first playlist as the default playlist. Will fix that. Thanks.