Mutation argument interfaces does not work

[dvndrsn]

Mutations implement the same options as ObjectType (because they create ObjectType under the hood), but using interfaces meta argument does not have the expected effect of applying the GraphQL Interfaces to the Mutation Payload ObjectType.

Mutation should be able to apply interfaces Meta argument to have the payload object type implement the desired interfaces.

See this thread for more discussion:

Originally posted by @jkimbo in #971