Some checks add data (cel's environment variables) as struct

• https://github.com/flanksource/canary-checker/blob/master/checks/exec.go#L74
• https://github.com/flanksource/canary-checker/blob/master/checks/aws_config.go#L60
• https://github.com/flanksource/canary-checker/blob/master/checks/folder_sftp.go#L48

and those cannot be converted to ref.Val.

This doesn't seem to work because the env can also contain durations which cannot be JSON marshalled

@adityathebe - can we not selectively go through the environment and convert only structs to maps, leaving the native types, time and duration as is ?