Commit 8201e545 introduced failing tests (e.g. `clj -X:dev:ee:ee-dev:drivers:test :only metabase.api.card-test/update-card-with-type-and-dataset-test`).

They all seem to originate from NPEs in `model-hydrate-based-on-upload` on the first condition in the `and` clause in the `based-on-upload` anonymous function. This PR just makes that first condition null-safe with a `some->` threading macro.