Bump mockitoVersion from 5.15.2 to 5.16.1 in /Plan (#4012)

Bumps `mockitoVersion` from 5.15.2 to 5.16.1.

Updates `org.mockito:mockito-core` from 5.15.2 to 5.16.1
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.15.2...v5.16.1)

Updates `org.mockito:mockito-junit-jupiter` from 5.15.2 to 5.16.1
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/compare/v5.15.2...v5.16.1)

---
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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Plan/build.gradle

@@ -91,7 +91,7 @@ subprojects {
         nkPlaceholderapiVersion = "1.4-SNAPSHOT"
 
         junitVersion = "5.11.4"
-        mockitoVersion = "5.15.2"
+        mockitoVersion = "5.16.1"
         seleniumVersion = "4.29.0"
         testContainersVersion = "1.20.5"
         awaitilityVersion = "4.2.2"