Add visual feedback for advertisement playing when using Spotify Free

[ethan-artos]

Currently displays previous track artwork whilst an ad is playing on the free tier, meaning it can be unclear that you're now listening to an ad rather than part of the current track. Especially during particularly experimental music or when used in conjunction with certain other advertising-focussed plugins 🚫😏

Some visual feedback that an ad is playing would solve this, even just a text overlay "advertisement" rather than specific information about the ad itself.

[will-stone]

Hey Ethan. Try out v3.3.0 when you get a chance and see if the advertisement text shows.

[ethan-artos]

So turns out the miniplayer does show the advertisement prompt text but only when the Spotify window is open on screen and in focus. If it is behind another window or minimized the miniplayer does not show any ad info.

A minor issue and I'd imagine a pain to test!

(tested with 3.3.0)