Restore old deletion behavior for Galleries
Restore old deletion behavior for Galleries

When galleries get "deleted" from CITI, they don't get unpublished,
which would trigger the creation of a `deleted:true` tombstone in
LPM Solr. Instead, their `WebMobilePublished` tag gets removed.
This doesn't generated a tombstone in LAKE, so we never actually
see them as removed, just orphaned.

This commit restores the old behavior for galleries to complement
the new behavior. We loop through all the galleries in our system
and check if they still exist upstream. See previous commit:

https://github.com/art-institute-of-chicago/data-aggregator/commit/775c75e

art-institute-of-chicago/data-aggregator,art-institute-of-chicago/data-aggregator,art-institute-of-chicago/data-aggregator