Bump spring from 6.1.14 to 6.1.15

Bumps `spring` from 6.1.14 to 6.1.15.

Updates `org.springframework:spring-framework-bom` from 6.1.14 to 6.1.15
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](spring-projects/spring-framework@v6.1.14...v6.1.15)

Updates `org.springframework:spring-test` from 6.1.14 to 6.1.15
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](spring-projects/spring-framework@v6.1.14...v6.1.15)

---
updated-dependencies:
- dependency-name: org.springframework:spring-framework-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-test
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -12,7 +12,7 @@ protobuf = "3.21.12"
 pulsar = "3.1.3"
 pulsar-reactive = "0.5.9"
 reactor = "2023.0.12"
-spring = "6.1.14"
+spring = "6.1.15"
 # tests
 assertj = "3.25.3"
 awaitility = "4.2.2"