[web] Add the cover artwork of Spotify playlists in the modal dialog

web-src/src/components/ModalDialogPlaylistSpotify.vue

@@ -17,6 +17,7 @@ export default {
   computed: {
     playable() {
       return {
+        image: this.item.images?.[0]?.url || '',
         name: this.item.name,
         properties: [
           { key: 'property.owner', value: this.item.owner?.display_name },