Fix problem javascript with read-unread notifications on notifications popup

[movilla]

Previous #3652

Now works :]

[jhass]

Hm guess I caused you some trouble with the changelog change, sorry. Try the following:

git checkout develop
git pull upstream develop
git checkout popup_notifications
git rebase develop # might cause some conflict, if so fix it, git add the file and do git rebase --continue
# edit Changelog.md to look nice
git add Changelog.md
git commit --amend
git push -f origin popup_notifications

[Raven24]

thanks!
merged (manually).

[movilla]

Aajjajaajjaja Thank you both :]