chore: remove enable-samples profile (#1284) (#600)

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
-  digest: sha256:a744afda1956beb7bd6dc8d0b740a7839bbe402e34e2f4ef24589074db53ceb0
+  digest: sha256:5b8c790f57cca57e6b37ba25f79291265c218cea3e6ba9714b001910ab3f1419

.kokoro/build.sh

@@ -91,7 +91,6 @@ samples)
 
         pushd ${SAMPLES_DIR}
         mvn -B \
-          -Penable-samples \
           -ntp \
           -DtrimStackTrace=false \
           -Dclirr.skip=true \