Add offer content to offer schema

[ngalala-adobe]

What are the schemas that are affected by the issue

https://github.com/adobe/xdm/blob/master/extensions/adobe/experience/decisioning/decisionevent.schema.json https://github.com/adobe/xdm/blob/master/extensions/adobe/experience/decisioning/option-detail.schema.json

What are examples of products that are impacted by the issue

Offer Decisioning

Changes Add option content (xdm:optionContent) to option schema and this should be an optional field