Remove unused reference store in image api

The image api already defines the backend used and does
not directly use the reference store backend. It also should not
directly use the reference store backend.

Signed-off-by: Derek McGowan <derek@mcg.dev>

cmd/dockerd/daemon.go

@@ -713,7 +713,6 @@ func buildRouters(opts routerOptions) []router.Router {
 		image.NewRouter(
 			opts.daemon.ImageService(),
 			opts.daemon.RegistryService(),
-			opts.daemon.ReferenceStore,
 		),
 		systemrouter.NewRouter(opts.daemon, opts.cluster, opts.builder.buildkit, opts.daemon.Features),
 		volume.NewRouter(opts.daemon.VolumesService(), opts.cluster),