Settings change breaks realtime service

### Current Behavior

When you change the settings in the realtime extension it seems to act as if the realtime extension was disabled for a brief time and that in turn causes the realtime systemd service to shut down.

### Steps to Reproduce

1. go to admin page and edit the settings of the realtime extension
2. save the new settings
3. see that the websocket connection now fails on the forum
4. see in the logs that the realtime systemd service shut down because it lost connection to the extension

### Expected Behavior

Simply saving the settings should not act like the extension was disabled entirely.

### Screenshots

_No response_

### Environment

- Flarum version: 2.0-rc8

### Output of `php flarum info`

### Possible Solution

_No response_

### Additional Context

_No response_

Start at the realtime extension's admin settings save flow and trace how it hands off to the systemd service, using the reported websocket failure and service logs. Done means saving settings keeps the websocket connection working without shutting down the realtime systemd service.

Written by the indexing model from the issue text.