Fix(Android): Add "unknown" authentication method option for Android

[mrejdak]

Added "unknown" authentication method option for older Android APIs that could return it

This is necessary according to https://developer.android.com/reference/android/hardware/biometrics/BiometricPrompt.AuthenticationResult#getAuthenticationType() and https://developer.android.com/reference/androidx/biometric/BiometricPrompt#AUTHENTICATION_RESULT_TYPE_UNKNOWN()

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of unknown biometric authentication results. Unknown authentication types are now properly distinguished and returned to the application, rather than being treated as a default case.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ad9b8fc3-affc-4464-b683-56012383b625

📥 Commits

Reviewing files that changed from the base of the PR and between 2aa8a1d and 36590ec.

📒 Files selected for processing (2)

• android/src/main/java/com/sbaiahmed1/reactnativebiometrics/ReactNativeBiometricsSharedImpl.kt
• src/types.ts

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📝 Walkthrough

Walkthrough

The pull request adds explicit handling for unknown biometric authentication results by mapping them to a new AuthType.Unknown enum value of -1. Previously, unknown authentication types defaulted to 0. This change updates both the Android implementation and TypeScript type definitions to distinguish between unknown and no-authentication scenarios.

Changes

Cohort / File(s)	Summary
Android Biometric Authentication android/src/main/java/com/sbaiahmed1/reactnativebiometrics/ReactNativeBiometricsSharedImpl.kt	Added explicit handling for BiometricPrompt.AUTHENTICATION_RESULT_TYPE_UNKNOWN, mapping it to -1 in both biometric success handlers instead of defaulting to 0.
TypeScript Type Definitions src/types.ts	Added Unknown = -1 enum member to AuthType export, enabling type-safe representation of unknown authentication results.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• feat(iOS + Android): Added returnAuthType flag #73: Modifies the same files (ReactNativeBiometricsSharedImpl.kt and src/types.ts) to extend authType mapping, directly aligned with this PR's unknown authentication type handling.
• fix(android + iOS): on Android correctly determining available authentication methods when signing; on iOS fix cancelButtonText #68: Updates Android authentication success handling in ReactNativeBiometricsSharedImpl.kt with related changes to how authenticator results are processed.

Poem

🐰 When auth returns a mystery unknown,
No longer treated as zero alone!
Now -1 marks the cryptic reply,
Types and logic aligned, oh my!
Unknown now has its rightful place. 🎯

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding support for an unknown authentication method on Android.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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