ibmcloud pi service-list should show Unauthorized error message if appropriate rather than an empty result

When I used the API key for a Service ID we had created, no workspaces were listed:$ ibmcloud pi service-listListing services under account [REDACTED] as user ...No instances found in the current account.This is wrong in two ways:1. There is a workspace there which I can see when logged in to the web UI2. There is no error message indicating lack of authorization or permissions to view the list of workspaces for this accountI discovered that the Access Group for this Service ID was missing, (apparently deleted by another engineer on this project while fixing an unrelated issue) so I created it again in the web UI. Once I had created the Access Group, the same command showed the desired output:$ ibmcloud pi service-listListing services under account Splunk CI-CD Production as user ...ID Namecrn:v1:bluemix:public:power-iaas:[REDACTED] [REDACTED]Please change the `ibmcloud pi service-list` command to indicate an error message like `ERROR 403 Forbidden: You don't have permissions to access the list of service instances associated with this account` rather than merely listing an empty result.