[Website]: Old image badges should be replaced with more specific serverless applies to scope

### Before you submit

- [x] This issue is about a documentation page, flow, or piece of content.

### Type of issue

Other

### What documentation page or section is affected

https://www.elastic.co/docs/explore-analyze/alerting/alerts/maintenance-windows

### What happened?

those security and observability badges should be applied using applies_to syntax instead

### Additional info

_No response_