Move ui_services_unittests into service_unittest.

services/ui/ws/test_manifest.json

 {
-  "name": "ui_service_unittests_app",
+  "name": "ui_service_unittests",
   "display_name": "Mus Window Server Unittests",
   "interface_provider_specs": {
     "service_manager:connector": {
       "provides": {
         "ui:window_tree_client": [
           "ui::mojom::WindowTreeClient"
         ]
       },
       "requires": {
         "*": [ "app" ],
-        "ui_service_unittests_app": [ "ui:window_tree_client" ],
+        "ui_service_unittests": [ "ui:window_tree_client" ],
         "ui": [
           "window_manager",
           "window_tree_host_factory"
         ]
       }
     }
   }
 }