tickets: schema not up to date

[enrico-spadaTR]

Context
It seems the schema.json for tickets endpoint is not up to date.
Specifically, according to Zendesk when the "via.source" is equal to "any_channel" it should include the following nested attributes service_info, supports_channelback, supports_clickthrough, registered_integration_service_name.

Impact
This causes missing missing data for the fields that are not included in the integration.