Update mongo driver to 4.9.1 n8n-2622

Editor assessment

The subject says the Mongo driver was updated to 4.9.1, which is clear, but the appended n8n-2622 ticket identifier is ticket junk jammed into the subject without separation, exactly what subject hygiene excludes, and it adds no meaning beside the PR reference. The fix type and house-style node scope are accurate for a driver upgrade. No body appears, and one line on why the upgrade was needed would have added value for a driver-level change that can shift behavior. The PR reference is well formed. Clear content diminished by ticket clutter: mediocre rather than good.