[dra] Trigger elasticsearch-hadoop dra build whenever we build a new …

…staging artifact (elastic#104084)

(cherry picked from commit 6a386ba)

.buildkite/pipelines/dra-workflow.yml

@@ -7,3 +7,13 @@ steps:
       image: family/elasticsearch-ubuntu-2204
       machineType: custom-32-98304
       buildDirectory: /dev/shm/bk
+  - wait
+  # The hadoop build depends on the ES artifact
+  # So let's trigger the hadoop build any time we build a new staging artifact
+  - trigger: elasticsearch-hadoop-dra-workflow
+    async: true
+    build:
+      branch: "${BUILDKITE_BRANCH}"
+      env:
+        DRA_WORKFLOW: staging
+    if: build.env('DRA_WORKFLOW') == 'staging'