Don't process metadata of non-tracks

This fixes mtui crashing whenever you process the metadata of any group
including a non-track too.

1 files changed, 1 insertions, 1 deletions

diff --git a/backend.js b/backend.js
index f2a9d99..b3e6564 100644
--- a/backend.js
+++ b/backend.js
@@ -629,7 +629,7 @@ class Backend extends EventEmitter {
     if (isGroup(item)) {
       const results = await Promise.all(item.items.map(x => this.processMetadata(x, reprocess, false)))
       counter += results.reduce((acc, n) => acc + n, 0)
-    } else process: {
+    } else if (isTrack(item)) process: {
       if (!reprocess && this.getMetadataFor(item)) {
         break process
       }