make sure to set lyrics nil when stopping

ui/browsing/nowplayingpage.go

@@ -205,9 +205,7 @@ func (a *NowPlayingPage) OnSongChange(song, _ *mediaprovider.Track) {
 	a.card.Update(song)
 	if song == nil {
 		a.card.SetCoverImage(nil)
-		return
-	}
-
+	} else {
 		a.imageLoadCancel = a.im.GetFullSizeCoverArtAsync(song.CoverArtID, func(img image.Image, err error) {
 			if err != nil {
 				log.Printf("error loading cover art: %v\n", err)
@@ -215,6 +213,7 @@ func (a *NowPlayingPage) OnSongChange(song, _ *mediaprovider.Track) {
 				a.card.SetCoverImage(img)
 			}
 		})
+	}
 
 	if a.tabs != nil && a.tabs.SelectedIndex() == 1 /*lyrics*/ {
 		a.updateLyrics()