Delete all info related to external exporters on pmm-admin list output

root@7bc0b41024e1:/pmm-client-1.7.0# pmm-admin list
pmm-admin 1.7.0

PMM Server      | 10.10.11.52 (insecure SSL, password-protected)
Client Name     | 7bc0b41024e1
Client Address  | 172.17.0.1 (172.17.0.3)
Service Manager | unix-systemv

No monitoring registered for this node identified as '7bc0b41024e1'.

Job name      Scrape interval  Scrape timeout  Metrics path  Scheme  Target           Labels                   Health
postgres-123  1m0s             10s             /metrics      http    172.17.0.3:8080  instance="7bc0b41024e1"  DOWN
root@7bc0b41024e1:/pmm-client-1.7.0# pmm-admin remove external:service postgres-123 --service-port=8080
External service removed.
root@7bc0b41024e1:/pmm-client-1.7.0# pmm-admin list
pmm-admin 1.7.0

PMM Server      | 10.10.11.52 (insecure SSL, password-protected)
Client Name     | 7bc0b41024e1
Client Address  | 172.17.0.1 (172.17.0.3)
Service Manager | unix-systemv

No monitoring registered for this node identified as '7bc0b41024e1'.

Job name  Scrape interval  Scrape timeout  Metrics path  Scheme  Target  Labels  Health