fix: Handle albumArtURI when extra attributes are given

When extra attributes are given to upnp:albumArtURI, the "main" value of
albumArtURI is assigned to '_' inside a dict. This seems to happen for tracks
played over DLNA. Handle this case so albumArtURI and consequently albumArtURL
is parsed correctly and doesn't error out.

Author: kcghost

lib/helpers.js

@@ -275,6 +275,9 @@ Helpers.dropIDNamespace = function (value) {
 
 Helpers.ParseDIDLItem = function (item, host, port, trackUri) {
   let albumArtURI = item['upnp:albumArtURI'] || null
+  if (albumArtURI && albumArtURI.constructor === Object) {
+    albumArtURI = albumArtURI['_']
+  }
   if (albumArtURI && Array.isArray(albumArtURI)) {
     albumArtURI = albumArtURI.length > 0 ? albumArtURI[0] : null
   }