build(deps): bump elasticsearch from 8.5.0-alpha.1 to 8.15.0-alpha.1

Bumps [elasticsearch](https://github.com/elastic/elasticsearch-rs) from 8.5.0-alpha.1 to 8.15.0-alpha.1.
- [Release notes](https://github.com/elastic/elasticsearch-rs/releases)
- [Commits](elastic/elasticsearch-rs@v8.5.0-alpha.1...v8.15.0-alpha.1)

---
updated-dependencies:
- dependency-name: elasticsearch
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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