iot: remove skip

Testing account has had its config changes such that this should now
work.

Change-Id: Ib5a4e61f9ad82a723c48d523543a1230de7d9085
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/39534
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Tyler Bui-Palsulich <tbp@google.com>
diff --git a/iot/apiv1/ListDeviceRegistries_smoke_test.go b/iot/apiv1/ListDeviceRegistries_smoke_test.go
index f010643..e15fb15 100644
--- a/iot/apiv1/ListDeviceRegistries_smoke_test.go
+++ b/iot/apiv1/ListDeviceRegistries_smoke_test.go
@@ -38,8 +38,6 @@
 var _ = time.Now
 
 func TestDeviceManagerSmoke(t *testing.T) {
-	t.Skip("Internal bug 128672764")
-
 	if testing.Short() {
 		t.Skip("skipping smoke test in short mode")
 	}