Network availability reports reachable when connected to a network with bad DNS.

### Steps to reproduce

1. Go on a network whose dns (and IP) is down - or manually set the DNS servers to some invalid value.
2. Optionally send a message.

### Outcome

#### What did you expect?

The network unavailable banner should be shown.

#### What happened instead?

The syncing banner shows forever an never goes away.
Messages simply fail to send with the error "Failed to send message" and the option to retry.

### Your phone model

13 pro max

### Operating system version

15.4

### Application version

1.8.19

### Homeserver

m.org

### Will you send logs?

Yes