Fix truncated_key value inserted on visual auth

When inserting a new set of API keys via the visual API endpoint, only 5 format
values were specified in the 3rd param passed to the $wpdb->insert(); however,
6 values were specified in the 2nd param. This meant that the truncted_key value
was being formatted as an integer only the first numerical characters of the last
7 character of the consumer key were being stored. For example, given a consumer
key value of ck_e91f2aeae6c3dea3045293a3dbdf55c317ad762c the truncated_key value
should be 7ad762c but instead, it was being stored at 7.

includes/class-wc-auth.php

@@ -212,6 +212,7 @@ class WC_Auth {
 				'%s',
 				'%s',
 				'%s',
+				'%s',
 				'%s'
 			)
 		);