Signing up on iOS causes email notifications switched on

### Steps to reproduce

1. Register on matrix.org from ios
2. email notifications will be switched on so you'll receive an e-mail per message

### Outcome

There is no way to disable email notifications from ios

### Your phone model

_No response_

### Operating system version

_No response_

### Application version

1.6.8

### Homeserver

_No response_

### Will you send logs?

No

Start with the reproduction steps in the issue: register on matrix.org using the iOS app and check whether email notifications are enabled. Investigate the iOS notification settings flow and verify that a newly registered user can disable email notifications; the issue is resolved when this can be done from iOS.

Written by the indexing model from the issue text.