The logic in parsing data files and converting them to data structures
accidentally removed healthchecks with no Name field, even though we
explicitly state in API documentation that is allowed.
We remove the check for "len(results.Checks) == 1" because if the length
of the array is more than 0, we know that it is not a zero value array.
This allows us to register a singular, unnamed check via the CLI.
Fixes#6796