Bump elastic/elasticsearch

Bumps the search-backend-containers group in /build/container/search-backend with 1 update: elastic/elasticsearch.


Updates `elastic/elasticsearch` from 8.15.1 to 8.15.2

---
updated-dependencies:
- dependency-name: elastic/elasticsearch
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: search-backend-containers
...

Signed-off-by: dependabot[bot] <[email protected]>

build/container/search-backend/elastic.Dockerfile

@@ -5,4 +5,4 @@
 #  * update `version.org.elasticsearch.latest` property in a POM file.
 #  * update the tags for 'elasticsearch-current' and 'elasticsearch-next' builds in ci/dependency-update/Jenkinsfile
 #
-FROM docker.io/elastic/elasticsearch:8.15.1
+FROM docker.io/elastic/elasticsearch:8.15.2