Rename shell namespace to service_manager

services/service_manager/tests/lifecycle/parent_manifest.json

 {
   "manifest_version":  1,
   "name": "service:lifecycle_unittest_parent",
   "display_name": "Lifecycle Unittest Parent",
   "capabilities": {
     "provided": {
-      "lifecycle_unittest:parent": [ "shell::test::mojom::Parent" ]
+      "lifecycle_unittest:parent": [ "service_manager::test::mojom::Parent" ]
     },
     "required": {
       "service:lifecycle_unittest_app": [
         "lifecycle_unittest:lifecycle_control"
       ]
     }
   }
 }