[artifacts/staging] Skip docker cloud verification (#132348)

Cloud builds should be skipped pending implementation of phase 2 of
daily releasable artifacts.

.buildkite/pipelines/artifacts.yml

@@ -56,6 +56,7 @@ steps:
     agents:
       queue: n2-2
     timeout_in_minutes: 30
+    if: "build.env('RELEASE_BUILD') == null || build.env('RELEASE_BUILD') == '' || build.env('RELEASE_BUILD') == 'false'"
     retry:
       automatic:
         - exit_status: '*'