fix X509Certificate::parse() throwing internal error for invalid input

[anonrig]

Fixes a sentry issue

[ask-bonk]

OK, inspect will truncate large values, so that's fine. This is a clean, well-scoped fix. The change is:

1. C++: Replace throwOpensslError with return kj::none when invalid cert data is passed
2. TypeScript: Check for null return and throw a user-friendly ERR_INVALID_ARG_VALUE
3. Type declaration: Updated to reflect X509Certificate | null return type
4. Tests: Good coverage of several invalid input scenarios

The only potential concern is the Node.js compatibility difference in error codes, but this is actually an improvement since the prior behavior was throwing an internal error (which is worse). The PR description says it fixes a Sentry issue, which confirms this was crashing in production.

LGTM

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