Importing mica.archive.aca_dark hits the dark_model deprecation warning

[jeanconn]

It looks like the aca_dark.__init__.py imports the local mica dark model and then we get the deprecation warning, even if the user did not explicitly import mica.archive.aca_dark.dark_model.

I don't recall if we still need that import from __init__.py and/or if there is a way to just skip the deprecation warning if it is just "passively" imported via that __init__.py.