Added tests cases for the DPoP validation and save scenarios

[pmathew92]

Changes

This PR adds UT tests for the DPoP thumbprint mismatch handling scenario

Testing

Please describe how this can be tested by reviewers. Be specific about anything not tested and reasons why. Since this library has unit testing, tests should be added for new functionality and existing tests should complete without errors.

• This change adds unit test coverage

• This change adds integration test coverage

• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

[Copilot]

Pull request overview

Adds unit test coverage for DPoP thumbprint persistence and DPoP state validation (missing key, client not configured, thumbprint mismatch, and migration backfill) in the credentials managers’ storage flows.

Changes:

• Extend existing save/clear credentials tests to assert com.auth0.token_type persistence and com.auth0.dpop_key_thumbprint removal where applicable.
• Add new unit tests covering DPoP thumbprint save/remove scenarios and DPoP validation failure modes (missing key, not configured, mismatch, migration backfill).
• Introduce test setup/teardown that mocks DPoPUtil.keyStore to deterministically simulate key presence/rotation.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
auth0/src/test/java/com/auth0/android/authentication/storage/SecureCredentialsManagerTest.kt	Adds DPoP-focused tests for encrypted credential flows, plus updates existing assertions for token type + thumbprint storage behavior.
auth0/src/test/java/com/auth0/android/authentication/storage/CredentialsManagerTest.kt	Adds DPoP-focused tests for non-encrypted credential flows and updates existing assertions to reflect thumbprint removal behavior.

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[utkrishtsahu]

LGTM