"Mark All as Read" does not remove notifications

[r10s]

the gist of "Mark All as Read" is to get chats out of ones way. therefore, and for consistency, also notifications should be removed when things are marked as read.

this issue may be one cause of stale notifications of #3991 , however, i doubt it is the only one as i was not using "Mark All as Read" until recently (i was not aware it exist :)

cmp #3979

[WofWca]

Might be related, or a duplicate #3982
#2438

[Simon-Laux]

I think we can treat this issue as own issue because it is reproducible.