Thibault Saunier 1faa88b1ff dashdemux2: Do not set empty string 'track_id'
This is not needed and generates g_warning like:

```
  Trying to set empty string on taglist field 'container-specific-track-id'. Please file a bug.
```

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8128>
2025-02-24 16:57:23 +00:00
..
2025-01-13 19:17:13 +01:00