ci(gcb): Remove redundant steps in test (#20446)

These are now built in after getsentry/onpremise#649

docker/cloudbuild.yaml

@@ -32,15 +32,10 @@ steps:
   - '-c'
   - |
     mkdir onpremise && cd onpremise
-    # TODO(byk): We may also build this part as a builder image everytime
-    #            there's a push to onpremise and use that image for
     curl -L "https://github.com/getsentry/onpremise/archive/master.tar.gz" | tar xzf - --strip-components=1
     # The following trick is from https://stackoverflow.com/a/52400857/90297 with great gratuity
     echo '{"version": "3.4", "networks":{"default":{"external":{"name":"cloudbuild"}}}}' > docker-compose.override.yml
     ./install.sh
-    docker-compose run --rm web createuser --superuser --email test@example.com --password test123TEST
-    docker-compose up -d
-    timeout 20 bash -c 'until $(curl -Isf -o /dev/null http://nginx); do printf "."; sleep 0.5; done' || docker-compose logs web
     ./test.sh || docker-compose logs nginx web relay
   timeout: 300s
 - name: 'gcr.io/cloud-builders/docker'