Validator report errors on CapabilitiesObject resource

[JojoWu19]

Since the CapabilitiesObject resource follows the same schema for the resource that the resource collection contains, there are some mandatory properties not in it. For example, the properties SubscriptionType andContext of EventDestination but Validator report these are errors:

/redfish/v1/EventService/Subscriptions/Capabilities
ERROR - SubscriptionType: Mandatory prop does not exist
ERROR - Context: Mandatory prop does not exist

[mraineri]

I may need to discuss this further with others. At least with some of the usage that we've seen so far, we expected required properties to be in the capabilities resource. However, I can certainly see why having things like "Context" in there for this don't make much sense.

I suspect we will likely need to make an exception to skip this check on these resources.

[JojoWu19]

Get it, thank you.