Accessibility: Notification announcements missing

### Steps to reproduce

We've had feedback from a screenreader user that our web & desktop notifications are not satisfactory and could do wtih some improvement. One appears the be a regression.

Suspected regression:
- Notifications don't show up at call.
- Element still makes a sound so "we're not entirely lost"
- The version prior said "New notifications from im.riot.app"

Other issue raised:
- If messages are sent to the room you are in, notifications are not sent
- Users also don't get a screenreader announcement either
- This means you have to manually check the timeline for new messages

We've had this feedback before and I believe ```aira-polite``` was suggested as a fix

### Outcome

#### What did you expect?
New messages should be told via screenreader so users know whats happening

#### What happened instead?
No announcement

### Operating system

Windows (might be mac too, not tested)

### Browser information

_No response_

### URL for webapp

_No response_

### Application version

_No response_

### Homeserver

_No response_

### Will you send logs?

No