Changes to Update Existing Connection

added the new optional request property preserve_secret_fields

added the non-success response with the status 400

added the non-success response with the status 404

added the non-success response with the status 409

added the optional property is_owner to the response with the 200 status

added the optional property owner to the response with the 200 status

added the optional property privacy to the response with the 200 status

added the optional property shares to the response with the 200 status

added the optional property unreadable_secret_fields to the response with the 200 status