[Uptime UI] hover interaction for synthetic screenshots

[katrin-freihofner]

Describe the feature:
We would like to show a bigger version of our captured screenshots when a user hovers the thumbnails. Please add this interaction to all thumbnails in the synthetic UI.

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)

[drewpost]

@katrin-freihofner re downloading image. I'm not sure that's the behaviour we'd like. If I can still right click, save image (ie use the default browser behaviour) then I'm happy. I can see a lot of accidental clicks and downloads as that isn't what I'd expexct to happen.

[paulb-elastic]

This is currently available on one particular part of the UI - when hovering the screen shot on the details (expanded) view, however this will be updated (in #80156) and there are some other places that don't currently have the hover, so leaving this issue open to track the requirement.