dump: handle new health-check

Handle the new health-check data reported by the jobs-api in the dump operation.

Previous to this patch, a YAML created by the dump operation would contain something like:

- command: ./test-cmd.sh
  continuous: true
  health_check: null
  image: bookworm
  name: test
  no-filelog: 'true'

Loeading this YAML would then yield:

WARNING: Unknown key 'health_check' in job 'test' definition

Bug: T335592 Signed-off-by: Arturo Borrero Gonzalez aborrero@wikimedia.org