When sqlite3_open_v2() fails, SQLite still assigns a database handle in a "sick" state. Such a handle may only be used to retrieve error information and must then be released with sqlite3_close(). DatabaseSync::Open() kept the handle in connection_, so after a failed open():

• database.isOpen incorrectly reported true.
• Every method passed the "database is not open" check and called SQLite APIs on the sick handle, which is an API misuse.
• database.function() and database.aggregate() leaked their user data in builds with SQLITE_ENABLE_API_ARMOR, because SQLite rejects calls on a sick handle with SQLITE_MISUSE before taking ownership of the user data. This is the leak reported by LeakSanitizer in the issue.
• open() could not be retried because the database appeared to be open.

This change closes and resets the connection handle when open() fails at any point, so a failed open() leaves the database closed, subsequent method calls throw ERR_INVALID_STATE, and open() can be retried once the underlying problem is resolved. Error reporting is unchanged: the error message is read from the sick handle before it is closed.

Before (v24.16.0):

$ node -e "
const { DatabaseSync } = require('node:sqlite');
const db = new DatabaseSync('/nonexistent-dir/x.db', { open: false, readOnly: true });
try { db.open(); } catch {}
console.log(db.isOpen);      // true
db.function('f', () => {});  // operates on the sick handle
"

Fixes: #63831