fix(deps): bump org.mockito:mockito-core from 4.9.0 to 5.20.0

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 4.9.0 to 5.20.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v4.9.0...v5.20.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.20.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

build.gradle

@@ -22,7 +22,7 @@ dependencies {
     implementation 'org.json:json:20250107'
     implementation 'com.nimbusds:oauth2-oidc-sdk:11.23'
 
-    testImplementation 'org.mockito:mockito-core:4.9.0'
+    testImplementation 'org.mockito:mockito-core:5.20.0'
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.10.2'
     testImplementation 'ch.qos.logback:logback-classic:1.2.11'
     testImplementation "com.github.tomakehurst:wiremock-jre8-standalone:2.35.0"