Rooms sorted after avatar change event

### Steps to reproduce

1. Change your avatar
2. Open the room list

### Outcome

#### What did you expect?

The room list doesn't get sorted according to the avatar change event and retains ordering of the latest message.

#### What happened instead?

The room list is sorted according to when the avatar change event got sent into the room.

### Your phone model

Pixel 6a

### Operating system version

Android 16

### Application version and app store

26.01.2 (202601022)

### Homeserver

Synapse 1.142.0

### Will you send logs?

Yes

### Are you willing to provide a PR?

No