Fix #1016: fixed broken fallback to album cover on artist card/detail

front/src/components/audio/artist/Card.vue

@@ -51,13 +51,13 @@ export default {
       return url
     },
     cover () {
-      if (this.artist.cover) {
+      if (this.artist.cover && this.artist.cover.original) {
         return this.artist.cover
       }
       return this.artist.albums.map((a) => {
         return a.cover
       }).filter((c) => {
-        return !!c
+        return c && c.original
       })[0] || {}
     },
   }

front/src/components/library/ArtistBase.vue

@@ -230,12 +230,12 @@ export default {
       )
     },
     cover() {
-      if (this.object.cover) {
+      if (this.object.cover && this.object.cover.original) {
         return this.object.cover
       }
       return this.object.albums
         .filter(album => {
-          return album.cover
+          return album.cover && album.cover.original
         })
         .map(album => {
           return album.cover