Bump org.springframework:spring-framework-bom from 6.1.14 to 6.1.15

Bumps [org.springframework:spring-framework-bom](https://github.com/spring-projects/spring-framework) from 6.1.14 to 6.1.15.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/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
...

Signed-off-by: dependabot[bot] <support@github.com>

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-org-springframework = "6.1.14"
+org-springframework = "6.1.15"
 org-springframework-security = "6.2.7"
 com-fasterxml-jackson = "2.15.4"
 nimbus-jose-jwt = "9.37.3"