build(deps): bump mockito from 5.15.2 to 5.16.0

Bumps `mockito` from 5.15.2 to 5.16.0.

Updates `org.mockito:mockito-core` from 5.15.2 to 5.16.0
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.15.2...v5.16.0)

Updates `org.mockito:mockito-junit-jupiter` from 5.15.2 to 5.16.0
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.15.2...v5.16.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.mockito:mockito-junit-jupiter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -1,7 +1,7 @@
 [versions]
 grpc = "1.70.0"
 log4j = "2.24.3"
-mockito = "5.15.2"
+mockito = "5.16.0"
 slf4j = "2.0.17"
 guava = "33.4.0-jre"
 assertj = "3.27.3"