Add 'suppressSend' and 'suppressDisplay' event types to proposition-event-type schema, Add 'reason' to proposition-action schema

[schezfaz]

What are the schemas that are affected by the issue

1. /proposition-event-type.schema.json
   - addition of two new event proposition types: suppressSend and suppressDisplay for events that have been suppressed during send and display respectively

2. /proposition-action.schema.json - addition of a new property reason to indicate why a proposition event has been suppressed

What are examples of products that are impacted by the issue

Adobe Journey Optimizer (Inbound Delivery Service)