fix(deps): update dependency org.mockito:mockito-core to v5.21.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
org.mockito:mockito-core	5.20.0 -> 5.21.0

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Release Notes

mockito/mockito (org.mockito:mockito-core)

v5.21.0

^{Changelog generated by Shipkit Changelog Gradle Plugin}

5.21.0

• 2025-12-09 - 17 commit(s) by Giulio Longfils, Joshua Selbo, Woongi9, Zylox, dependabot[bot]
• Bump graalvm/setup-graalvm from 1.4.3 to 1.4.4 (#​3768)
• Bump graalvm/setup-graalvm from 1.4.2 to 1.4.3 (#​3767)
• Bump actions/checkout from 5 to 6 (#​3765)
• Adds output of matchers to potential mismatch; Fixes #​2468 (#​3760)
• Forbid mocking WeakReference with inline mock maker (#​3759)
• StackOverflowError when mocking WeakReference (#​3758)
• Bump actions/upload-artifact from 4 to 5 (#​3756)
• Bump graalvm/setup-graalvm from 1.4.1 to 1.4.2 (#​3755)
• Support primitives in GenericArrayReturnType. (#​3753)
• ClassNotFoundException when stubbing array of primitive type on Android (#​3752)
• Bump graalvm/setup-graalvm from 1.4.0 to 1.4.1 (#​3744)
• Bump gradle/actions from 4 to 5 (#​3743)
• Bump org.graalvm.buildtools.native from 0.11.0 to 0.11.1 (#​3738)
• Bump com.diffplug.spotless:spotless-plugin-gradle from 7.2.1 to 8.0.0 (#​3735)
• Bump graalvm/setup-graalvm from 1.3.7 to 1.4.0 (#​3734)
• Bump org.assertj:assertj-core from 3.27.5 to 3.27.6 (#​3733)
• Bump errorprone from 2.41.0 to 2.42.0 (#​3732)
• Feat: automatically detect class to mock in mockStatic and mockConstruction (#​3731)
• Return completed futures for unstubbed Future/CompletionStage in ReturnsEmptyValues (#​3727)
• automatically detect class to mock (#​2779)
• Incorrect "has following stubbing(s) with different arguments" message when using Argument Matchers (#​2468)

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[github-actions]

SpotBugs

Category	Base	New
Bad practice	34	34
Correctness	34	34
Dodgy code	26	26
Internationalization	6	6
Malicious code vulnerability	49	49
Multithreaded correctness	11	11
Performance	8	8
Total	168	168

[nextcloud-android-bot]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-library-integrationTests/4777-IT-master-02-34/debug/