Multiple notifications when a specific users send a single message

### Steps to reproduce

1. Half Shot pings me
2. I get several notifications for it

### Outcome

#### What did you expect?

receive a single notification

#### What happened instead?

received several

Both him and I rageshook:
- https://github.com/matrix-org/element-web-rageshakes/issues/21362
- https://github.com/matrix-org/element-web-rageshakes/issues/21363

### Operating system

macOS

### Application version

Element Nightly version: 2023041801 Olm version: 3.2.12

### How did you install the app?

https://element.io/get-started#nightly

### Homeserver

Synapse 1.77

### Will you send logs?

Yes