Universal Document Approvals needs message to reviewer/approver feature

[#1]

Description - When kicking off a Universal Approval (document approval) we need the ability to add a message prior to sending to the reviewers. Proofing workflow has this ability. 

Why is this feature important to you - It's consistent for both Workfront owners and reviewers/approvers as they experience in Proofing workflow.

How would you like the feature to work - After choosing my reviewers/approvers, I'd like to type in a message that will appear in the notification they receive.

Current Behaviour - I have to add a message in the "Updates" feature which then disconnects from the review/approval notification. Leads to confusion and multiple notifications on the same document.