Search verification sessions with flexible filtering.

Filters combine using AND logic between different filter types, and OR logic
within each filter's values. For example, filtering by status=[success, fail]
and email=[[email protected], [email protected]] returns sessions that match
(success OR fail) AND (either email).

In addition to the parameters listed below, this endpoint also supports searching
by your custom fields. To filter by a custom field value, specify the field name
as a query parameter prefixed with custom_. For example, to search for verifications
with a specific value for the custom field store_id, add custom_store_id=xyz as
a query parameter in your request.