deps: bump libraries-bom from 26.18.0 to 26.19.0 (#2032)

Bumps [libraries-bom](https://github.com/googleapis/java-cloud-bom) from 26.18.0 to 26.19.0.
- [Release notes](https://github.com/googleapis/java-cloud-bom/releases)
- [Changelog](https://github.com/googleapis/java-cloud-bom/blob/main/release-please-config.json)
- [Commits](googleapis/java-cloud-bom@v26.18.0...v26.19.0)

---
updated-dependencies:
- dependency-name: com.google.cloud:libraries-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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