Update snyk ci job to use branch as target reference (#95794) (#95801)

Author: breskeby

.ci/jobs.t/elastic+elasticsearch+periodic+snyk-dependency-monitoring.yml

@@ -18,4 +18,4 @@
           export SNYK_TOKEN=$(vault read -field=token secret/elasticsearch-ci/snyk)
           unset VAULT_TOKEN
           set -x
-          $WORKSPACE/.ci/scripts/run-gradle.sh uploadSnykDependencyGraph
+          $WORKSPACE/.ci/scripts/run-gradle.sh uploadSnykDependencyGraph -PsnykTargetReference=%BRANCH%