Notifications are not cleared, but instead flash

### Steps to reproduce

Message notifications are not cleared on read of a 1-to-1 DM, instead they will be momentarily hidden, before flashing with an incrementing number of messages in the menu sidebar.

This "flashing" occurs when any activity occurs within the DM, such as starting to type a message, or the conversation partner typing a message.

### Outcome

#### What did you expect?
I expected chat notifications to clear on read and stay cleared

#### What happened instead?
They were not cleared, and the number of messages continue to increase with each new message into the chat window.

### Operating system

macOS

### Browser information

Chrome 108.0.5359.124

### URL for webapp

Element version: 1.11.19 Olm version: 3.2.12

### Application version

Element version: 1.11.19 Olm version: 3.2.12

### Homeserver

Synapse

### Will you send logs?

No