Add new/Update existing endpoint to enable programmatic retrieval of the email test variants data for an email with A/B Test

Currently due to the limitation of email asset endpoints - email that is part of a program that is using  Email Testing (A/B Test, or Champion/Challenger Test) is not available for querying using  Get Email by Id, Get Email by Name,  Get Emails - to overcome this users tend to use the activities endpoint to get the test email details. Emails with A/B tests have an ".Whole Emails Test"/".Subject Line Test" appended to their name in the activities API endpoint response but there is little info supplied for the test variants - it would be great if response includes few more attributes with the additional details for the test variants (like subject lines, from name, send times, etc.). The test variant id currently supplied in the attributes parameter helps little in identifying what and how actually the test variant was configured (subject lines, from name, send times, etc.).