Improve unmapped error exception to include the mapping function name and the error code

[vcsjones]

When we encounter an unmapped OpenSSL error, retail builds do not include any information about what the error was. This adds some exception text to help diagnose.

Contributes to #114129.

[Copilot]

Pull Request Overview

This PR enhances unmapped OpenSSL error handling by including the mapping function name and the raw error code in the thrown exception to aid diagnostics.

• Updated MapOpenSsl*Code methods to throw a detailed exception instead of a generic one.
• Added a GetUnmappedCodeException helper that formats the error message.
• Introduced a new resource string for the unmapped OpenSSL code error.

Reviewed Changes

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

File	Description
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslX509ChainProcessor.cs	Replaced generic CryptographicException throws with calls to GetUnmappedCodeException, and added that helper method.
src/libraries/System.Security.Cryptography/src/Resources/Strings.resx	Added Cryptography_UnmappedOpenSslCode resource string for formatting the new exception message.

Comments suppressed due to low confidence (1)

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/OpenSslX509ChainProcessor.cs:1423

• Consider adding unit tests to verify that when an unmapped OpenSSL error code is encountered, the exception message includes the correct function name and error code.

private static CryptographicException GetUnmappedCodeException(string functionName, int code)

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[bartonjs]

LGTM.

I sort of want to ask "should we get rid of the assert now that we have enough data?", but, eh, in a Debug build we should definitely be seeing these and mapping them... and it shows "this exception is not something we ever want someone to see". So... I like it as it is. ("Good talk.")