TypesImplementInterfaces check fails for interfaces implementing interfaces

[KammererTob]

With v15.0 and the support for interfaces implementing interfaces it seems like the TypesImplementInterfaces fails in some scenarios. This line:

https://github.com/graphql-java/graphql-java/blob/master/src/main/java/graphql/schema/validation/TypesImplementInterfaces.java#L175

only works when one is of type GraphQLObjectType and the other of GraphQLInterfaceType. There can be cases where both are interfaces now.

interface Trait {
    name: String
}

interface MammalTrait implements Trait {
    name: String
}

interface Animal {
    traits: [Trait]
}

type Dog implements Animal {
    traits: [MammalTrait]
}

This leads to:
Caused by: graphql.schema.validation.InvalidSchemaException: invalid schema:
object type 'Dog' does not implement interface 'Animal' because field 'traits' is defined as '[MammalTrait]' type and not as '[Trait]' type