Update Journey Version Step Events XDM Mixin to add new attributes

## What are the schemas that are affected by the issue
https://github.com/adobe/xdm/blob/master/extensions/adobe/experience/journeyOrchestration/stepEvents/journeyStepEventCommonFieldsMixin.schema.json

## What are examples of products that are impacted by the issue
Journey Orchestration, Customer Journey Management

Start by reading extensions/adobe/experience/journeyOrchestration/stepEvents/journeyStepEventCommonFieldsMixin.schema.json. The issue does not specify which attributes to add, so clarify the required fields and their definitions for Journey Orchestration and Customer Journey Management before making changes; done means the agreed attributes are represented in this mixin.

Written by the indexing model from the issue text.