Unread badge stays at 1 if the last event in the room was an e2e verification

**Describe the bug**
If the last event in a room is an e2e-encryption verification, the unread badge stays at 1 even if all chats are completely read.

**To Reproduce**
Steps to reproduce the behavior:
1. Start an e2e-encryption verification with another user
2. Sucessfully validate each other
3. Don't write anything, close Element
4. The app icon should show a "1" badge, as well as the contacts tab

**Expected behavior**
The badge should disappear because there are no unread messages left.