[pigeon]: Bump mockito-core (#2833)

Bumps [mockito-core](https://github.com/mockito/mockito) from 3.+ to 4.9.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](https://github.com/mockito/mockito/commits/v4.9.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-type: direct:production
...

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packages/pigeon/platform_tests/alternate_language_test_plugin/android/build.gradle

@@ -47,6 +47,6 @@ android {
 
     dependencies {
         testImplementation 'junit:junit:4.+'
-        testImplementation "org.mockito:mockito-core:3.+"
+        testImplementation "org.mockito:mockito-core:4.+"
     }
 }