Refactor smoke test setup to script

Avoid interpolation backflips with buildkite by extracting to a script.

Author: donoghuc

.buildkite/pull_request_pipeline.yml

@@ -136,11 +136,7 @@ steps:
         - limit: 3
     command: |
       set -euo pipefail
-      source .buildkite/scripts/common/vm-agent.sh
-      ./gradlew --stacktrace artifactDockerObservabilitySRE
-      logstash_version="$(awk -F':' '{ if ("logstash" == $1) { gsub(/ /,"",$2); print $2; exit } }' versions.yml)-SNAPSHOT"
-      docker run docker.elastic.co/logstash/logstash-observability-sre:${logstash_version} \
-        logstash -e 'input { generator { count => 3 } } output { stdout { codec => rubydebug } }'
+      ci/run-observability-sre-container-smoketest.sh
 
   - label: ":lab_coat: Integration Tests - FIPS mode / part 1"
     key: "integration-tests-fips-part-1"

ci/run-observability-sre-container-smoketest.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+source .buildkite/scripts/common/vm-agent.sh
+./gradlew --stacktrace artifactDockerObservabilitySRE
+logstash_version="$(awk -F':' '{ if ("logstash" == $1) { gsub(/ /,"",$2); print $2; exit } }' versions.yml)-SNAPSHOT"
+docker run docker.elastic.co/logstash/logstash-observability-sre:${logstash_version} logstash -e 'input { generator { count => 3 } } output { stdout { codec => rubydebug } }'