Delete popped value from store after loading it
Delete popped value from store after loading it

Previously in `DistributedArrayStore`'s `pop`, only the data on disk was
removed. However the Dask Array in `_memstore` also needs to be cleaned
up. This includes canceling the `Future`s of the Dask Array so that no
one tries to reload it from disk (given the disk representation has
expired). Instead of trying to recreate the nice process already in
`DistributedArrayStore`'s `__delitem__`, go ahead and call `__delitem__`
after loading the data from disk into Distributed's persisted memory.
This handles dropping the Dask Array from our in memory cache, canceling
the `Future`s to block other computations dependent on that result, and
removing the on disk data.

nanshe-org/nanshe_workflow,DudLab/nanshe_workflow