[in_app_pur]: Bump org.mockito:mockito-core (#7094)

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 4.7.0 to 5.1.1.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v4.7.0...v5.1.1)

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

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

packages/in_app_purchase/in_app_purchase_android/example/android/app/build.gradle

@@ -108,7 +108,7 @@ flutter {
 dependencies {
     implementation 'com.android.billingclient:billing:5.0.0'
     testImplementation 'junit:junit:4.13.2'
-    testImplementation 'org.mockito:mockito-core:4.7.0'
+    testImplementation 'org.mockito:mockito-core:5.1.1'
     testImplementation 'org.json:json:20220924'
     androidTestImplementation 'androidx.test:runner:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'