Query methods returning an aggregate implementing `Streamable` considered collection executions

[odrotbohm]

Given an aggregate

class StreamableAggregate implements Streamable<Object> { }

And a repository method

interface StreamableAggregateRepository extends Repository<StreamableAggregate, Object> {

  StreamableAggregate findBy();
}

the findBy() method will be considered a collection query as QueryMethod.isCollectionQuery() unwraps all types implementing Streamable directly. We need to put guards in place that particularly rule out types assignable to the root domain type.