Build: Bump com.google.cloud:libraries-bom from 26.28.0 to 26.40.0

Bumps [com.google.cloud:libraries-bom](https://github.com/googleapis/java-cloud-bom) from 26.28.0 to 26.40.0.
- [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@v26.28.0...v26.40.0)

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

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

gradle/libs.versions.toml

@@ -41,7 +41,7 @@ findbugs-jsr305 = "3.0.2"
 flink117 = { strictly = "1.17.2"}
 flink118 =  { strictly = "1.18.1"}
 flink119 =  { strictly = "1.19.0"}
-google-libraries-bom = "26.28.0"
+google-libraries-bom = "26.40.0"
 guava = "33.2.0-jre"
 hadoop2 = "2.7.3"
 hadoop3-client = "3.3.6"