[Android] Fix Android SSL exception propagation in certificate validation

[kotlarmilos]

Summary

This fixes Android-specific SSL exception handling to explicitly propagate AuthenticationException when certificate validation fails. Additionally, in SSL handshake even when validation exceptions were detected, the SSL handshake continued instead of failing immediately.

Changes

• Explicitly create and throw AuthenticationException when certificate validation fails
• Ensure SSL handshake is immediately terminated upon validation failure
• Propagate exceptions via SecurityStatusPal to prevent timeouts

[Copilot]

Pull Request Overview

This PR fixes Android-specific SSL exception handling to ensure certificate validation exceptions are properly propagated and cause immediate handshake failure. The issue was that certificate validation failures were not being converted to AuthenticationException and SSL handshakes continued even when validation failed, leading to timeouts instead of proper error reporting.

Key changes:

• Add explicit AuthenticationException creation when certificate validation fails
• Implement early termination of SSL handshake when validation exceptions are detected
• Ensure proper exception propagation through SecurityStatusPal to prevent timeouts

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
SslStreamPal.Android.cs	Adds validation exception checking before and after handshake attempts with proper status code handling
SslStream.Android.cs	Creates AuthenticationException when certificate validation fails and adds using directive for Authentication namespace

[Copilot]

The validation exception is retrieved twice in the same method (lines 207 and 226). Consider storing the result in a variable that's updated only when needed to avoid redundant property access.

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[kotlarmilos]

/azp run runtime-extra-platforms

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[kotlarmilos]

This fixes the CI but is not the proper fix. Validation can return false even when there is no custom validation through ServerCertificateCustomValidationCallback.