chore(deps): bump org.mockito:mockito-core

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.14.2 to 5.15.2.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.14.2...v5.15.2)

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

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

Author: dependabot[bot]

components/serialization/multipart/gradle/dependencies.gradle

@@ -1,7 +1,7 @@
 dependencies {
     // Use JUnit Jupiter API for testing.
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.11.4'
-    testImplementation 'org.mockito:mockito-core:5.14.2'
+    testImplementation 'org.mockito:mockito-core:5.15.2'
 
     // Use JUnit Jupiter Engine for testing.
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'