Add more browser test (#3944)
Add more browser test (#3944)

- Ability to restore a style when it was removed.
- Ability to watch for a source style and link positions.
- Ability to remove override when style was removed.
- Ability to react on dynamic style creation.
- Ability to react on inserting something into a style dynamically (sheet.insertRule(...)).
darkreader/darkreader,alexanderby/darkreader,darkreader/darkreader,alexanderby/darkreader,alexanderby/darkreader,darkreader/darkreader