[php-src] PR #23070: Honor ERRMODE_SILENT in pdo_raise_impl_error

Pull Request: https://github.com/php/php-src/pull/23070 Author: iliaal ERRMODE_SILENT is documented to record the error without raising anything, but pdo_raise_impl_error falls through to php_error_docref for every mode except EXCEPTION, so $pdo->getAttribute(123456) warns under SILENT. The early return is there, disabled behind #if 0, because returning ahead of the memcpy left errorInfo() reporting the previous SQLSTATE. Copying the code first and returning after it drops the warning and keeps errorInfo() accurate. GH-12032 reported the same behaviour, and the suggestion there was that changing it may want internals discussion, so this targets master rather than a stable branch.