No Avatar for rooms containing a `m.room.name: ""` state entry

### Steps to reproduce

1. From @a:domain.org create a new group with a user you already have a dm (@b.domain.org) with. (normal group, group name "test")
2. join with both users
3. observe no avatar on EX (since its a group with no avatar)
4. Convert the room into dm on EW on both accounts (just the acc used on EX should be sufficient)
5. RENAME the group to `""` (`m.room.name`) -> it will get renamed on EX to the other users name (DM semantics). It will NOT load the avatar! (it will generate an avatar using the first letter however...)

#### What did you expect?
To also see the avatar in the room list.
#### What happened instead?
I did see a generated avatar and when going into the room details I could see the two avatars in the nice EX stacked avatar DM design.

### Context
The difference to [this](https://github.com/element-hq/element-x-android/issues/3581) similar sounding issue is:
- https://github.com/element-hq/element-x-android/issues/3581
- no avatar due to heros not being populated (due to a third member historical or as a functional_member)
- This issue:
- no avatar due to m.room.name logic branch getting triggered

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

_No response_

### Homeserver

_No response_

### Will you send logs?

Yes

### Are you willing to provide a PR?

Yes