docker: ask the seat mesh-artifact-sweep for the images a machine's declarations name, as ADR 0121 names the seat (issue 1955)

modules/docker/cmd/docker-tools/prune_images_test.go

@@ -43,7 +43,7 @@ func imagesMachine() *fake {
 
 func declaring(t *testing.T, answer string) Asker {
 	return func(key string, body any) (json.RawMessage, error) {
-		if key != "seat:artifact-store.images" {
+		if key != "seat:mesh-artifact-sweep.images" {
 			t.Errorf("asked %s", key)
 		}
 		if b, _ := body.(map[string]any); b["node"] != "laptop" {