Exclude deleted threads from unread count
Exclude deleted threads from unread count

Closes #8504.

luanlv/lila,luanlv/lila,luanlv/lila,arex1337/lila,luanlv/lila,luanlv/lila,arex1337/lila,arex1337/lila,arex1337/lila,luanlv/lila,luanlv/lila,arex1337/lila,arex1337/lila,arex1337/lila