multiple group labels, only one notification

**Describe the bug**
I noticed that URLs tagged with multiple labels only launch a single notification, only for one of them, apparently randomly choosen, while I expect all notifications are fired, for all group labels defined for that URLs.

**Version**
0.54.4.

**How did you install?**
Docker

**To Reproduce**
1. Define an URL to monitor
2. Add two group labels
3. Edit every group, defining different notification settings for each one
4. Run URL change monitor
5. You will get only one notification, not two.

**Expected behavior**
Multiple notifications, not only one.

**Desktop**
- OS: ArchLinux
- Browser Firefox
- Version 148.0