fix: make HTTP2 invalid headers recoverable (#4356)

[tawseefnabi]

• Add try-catch blocks around all session.request() calls in writeH2
• Implement automatic retry logic for ERR_HTTP2_INVALID_CONNECTION_HEADERS
• Handle expectContinue, regular request, and CONNECT method paths
• Destroy session and retry with new connection on first error
• Abort gracefully if retry also fails
• Add comprehensive test coverage for error handling

Fixes #4356

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[Uzlopak]

@metcoder95 Looks like AI slop.