Remove or explain "Current Alarms" section when empty

[elinol]

When Current Alarms list is empty we should remove that section from device health in UI, alternatively tell that list is empty.
It looks a bit odd with a header without any content.

[joshk]

One idea, if there are no active alarms we should change the text to No active alarms with a link below it that reads Learn how to setup Device alarms that links to some nerves_hub_link code/docs/guide?

[elinol]

I'm not sure there is any docs updated enough to link to, can only find this: https://github.com/nerves-hub/nerves_hub_link?tab=readme-ov-file#alarms

let's start with No active alarms?