Can not remove tag of existing bookmark

Data

• Shiori version: 1.8.0
• Database Engine: SQLite
• Operating system: Ubuntu 22.04 / Docker
• CLI/Web interface/Web Extension:

Describe the bug / actual behavior

After adding a Bookmark I cannot remove existing tags. When modifying the tags line, it only accepts new tags, but does not remove existing tags.

Expected behavior

Tags can be added and removed by modifying the comma separated list of tags in the edit dialog.

To Reproduce

1. Save Bookmark with tags
2. Edit Bookmark
3. Remove one or all of the tags
4. Save the bookmark
5. Bookmark still has all of the tags, even after a full refresh of the site.

Screenshots

If applicable, add screenshots to help explain your problem.

Notes

I was also surprised that I have to add comma to separate tags instead of splitting on whitespace. If that's wanted, I'll adapt though.