Fix list caching for streaming sources

[dylanratcliffe]

For sources that support ListStream we cache the items as we find them. The problem with this is that if we get to say page 4 of 10 and then the context times out, we'll have only cached some of the items, however if the user then runs another query they will now hit the cache which is bad since it won't return all the available items and won't retry.

Maybe we should be caching at the HTTP level instead?