Push rules aren't updated in the NSE when you modify them in the app.

### Steps to reproduce

1. Start with the default push rules that give you silent notifications for group chats:

2. In the app go to Settings | Default Notifications and uncheck all of these, and then recheck them (forcing all to now be noisy notifications).
3. Receive a notification from a group chat.

### Outcome

#### What did you expect?
The incoming notification to now play a sound

#### What happened instead?
The notification is still silent.

A quick investigation into this and the push rules are updated in `MXNotificationCenter`, however the NSE uses `MXBackgroundPushRulesManager` and is running in a separate process.

The new rules do eventually take effect, for example if the NSE crashes or if you restart your phone.

Marked as S-Major as toggling notification sounds seems like a pretty core feature of the app to me.

### Your phone model

iPhone 12

### Operating system version

iOS 15.5

### Application version

1.8.23

### Homeserver

_No response_

### Will you send logs?

No