current_job property in cluster list API call should be object instead of string

[gnehapk]

Currently the current_job property for each cluster inside \clusters API call is string. It should be object ideally.

"current_job":"{\"status\": \"finished\", \"job_name\": \"UnmanageCluster\", \"job_id\": \"286923ce-6445-4dc3-984c-2e41d4a21b77\"}"