[stable27] fix(browser): Don't create web notifications for old notifications

[backportbot[bot]]

Backport of #1943

Warning, This backport's changes differ from the original and might be incomplete ⚠️

Todo

• [ ] Review and resolve any conflicts

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[nickvergessen]

/compile /