This updates the flux integration to use the `flux/array` package rather
than directly using the `arrow/array` package.
Flux recently switched to wrapping the array types from arrow and
creating its own array package to be used for table columns instead of
directly referencing the arrow package. This allows us to keep a
consistent interface, but potentially change internal implementations
without changing downstream consumers. Most recently, the
`*array.String` type has some of its own optimizations for certain array
patterns.
This change updates the flux integration to use the new API.
Sam Arnold
Jonathan A. Sternberg
Daniel Moran