Created DM ended up causing notifications in rooms and people

## Steps to reproduce / what went wrong

1. Create a DM with someone (in my case, from the 'direct message' link of user/member info)
2. Say something that will cause them to message you back
3. Go look at other rooms/spaces
4. Receive messages from that user
5. Note that your 'Rooms' sublist lights up. From the 'Home' view, the DMs sublist also lights up

## Context

The user I sent a DM to is a member of a space where I was seeing this behaviour, though I don't know if that's related. I can believe that the client missed the tag change (rooms -> DM) so the notification state stuff might have gotten confused.

Restarting the client cleared it up.

## Device info

Windows 10, Nightly