demux_edl: support global_tags with delay_open

The delay_open mechanism used by
--script-opt=ytdl_hook-all_formats=yes breaks setting metadata with
global_tags because tl->track_layout is NULL. See adcf51d cbb8f53
8ea7aa5.

Fix this by applying tags to the EDL timeline in this case.

Tags must still be applied to tl->track_layout when available for them
to work with local EDL files.

Author: guidocella

demux/demux_edl.c

@@ -560,12 +560,11 @@ static struct timeline_par *build_timeline(struct timeline *root,
     if (!tl->track_layout && !tl->delay_open)
         goto error;
     if (!root->meta)
-        root->meta = tl->track_layout;
+        root->meta = tl->track_layout ? tl->track_layout : root->demuxer;
 
     // Not very sane, since demuxer fields are supposed to be treated read-only
     // from outside, but happens to work in this case, so who cares.
-    if (root->meta)
-        mp_tags_merge(root->meta->metadata, edl_root->tags);
+    mp_tags_merge(root->meta->metadata, edl_root->tags);
 
     mp_assert(tl->num_parts == parts->num_parts);
     return tl;