Remove netcheker as we now use hydrophone for network tests (#13058)

roles/validate_inventory/tasks/main.yml

@@ -49,7 +49,6 @@
   assert:
     that:
       - download_run_once | type_debug == 'bool'
-      - deploy_netchecker | type_debug == 'bool'
       - download_always_pull | type_debug == 'bool'
       - helm_enabled | type_debug == 'bool'
       - openstack_lbaas_enabled | type_debug == 'bool'