testing: sort force-automated hosts

[mohammed90]

The forcedAutomatedNames variable is a map, which is not guaranteed to be ordered in Go. By mere chance., the CI run on the PR #6712 was successful. The CI run on master after merge (https://github.com/caddyserver/caddy/actions/runs/12483804029/job/34840195488) failed with this diff showing the expected vs actual:

 - 					"automated1.example.com",
 - 					"automated2.example.com"
 + 					"automated2.example.com",
 + 					"automated1.example.com"

Sorted strings would have automated1 first, so sorting the slice before marshalling ensures stable output.

[francislavoie]

Thanks!