Routes giving error after deleting endpoints without removing them from routes

## Describe the bug

Routes giving error after deleting endpoints without removing them from routes.

We're sorry, but something went wrong.
If you are the application owner check the logs for more information.

```
2026-05-13 07:32:27 +0000 ERROR GET /org/xxx/servers/xxx/routes (500) event=request transaction=312812cac6c6f0fbff73 controller=RoutesController action=index format=html method=GET path=/org/xxx/servers/xxx/routes request_id=5d0e4303-428d-40b0-9c4d-ed53eb58b36b ip_address=2001:xxx status=500 db_runtime=41.518762707710266 exception_class=ActionView::Template::Error exception_message=undefined method 'description' for nil exception_backtrace=/opt/postal/app/app/views/routes/index.html.haml:43:in 'block (2 levels) in _app_views_routes_index_html_haml___3853192624077728282_23664'\n/usr/local/bundle/gems/actionview-7.1.5.2/lib/action_view/helpers/capture_helper.rb:50:in 'block in ActionView::Helpers::CaptureHelper#capture'\n/usr/local/bundle/gems/actionview-7.1.5.2/lib/action_view/buffers.rb:75:in 'ActionView::OutputBuffer#capture'\n/usr/local/bundle/gems/actionview-7.1.5.2/lib/action_view/helpers/capture_helper.rb:50:in 'ActionView::Helpers::CaptureHelper#capture'
2001:xxx - - [13/May/2026:07:32:27 +0000] "GET /org/xxx/servers/xxx/routes HTTP/1.1" 500 1477 0.2584
```

## To Reproduce

1. Go to Routes
2. Add endpoints
3. Create routes with endpoints
4. Delete endpoints
5. Error

## Expected behaviour

Warning and no error

## Environment details

- OS: Debian 12
- Browser any
- Version 3.3.5, 3.3.6
- Type any