Bump org.springframework:spring-framework-bom from 7.0.0-M7 to 7.0.0-M8

Bumps [org.springframework:spring-framework-bom](https://github.com/spring-projects/spring-framework) from 7.0.0-M7 to 7.0.0-M8.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](spring-projects/spring-framework@v7.0.0-M7...v7.0.0-M8)

---
updated-dependencies:
- dependency-name: org.springframework:spring-framework-bom
  dependency-version: 7.0.0-M8
  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 = "3.25.8"
 pulsar = "4.0.6"
 pulsar-reactive = "0.7.0"
 reactor = "2025.0.0-M6"
-spring = "7.0.0-M7"
+spring = "7.0.0-M8"
 # tests
 assertj = "3.27.4"
 awaitility = "4.3.0"