No user feedback if backend server is not running

[illume]

Describe the bug

If the backend server crashes it would be good to show the user. Perhaps letting them recover.

To Reproduce

Steps to reproduce the bug:

1. Start Headlamp.
2. Stop backend server.
3. See the UI doesn't show it's crashes.

[Faakhir30]

Ig it does show Lost connection to cluster
Tried:

make run-backend
make run-frontend

then stoped backend terminal.

State produced: