Issue Summary

Metadata is ignored when you create a booking.

Steps to Reproduce

1. Add metadata to query parameters of the event link, e.g. http://localhost:3000/john-foo-zrurxq/30min?metadata[user_id]=123
2. Open the link in the browser;
3. Book a meeting.
4. Call the GET v1/bookings endpoint and find created booking.

Expected: To see created booking with metadata provided in query params.
Actual: metadata is null.

_CAL-984