## About The Pull Request
subtypes of `/obj/item/food/grown` have no reason to not be spawned by
the `create_and_destroy` unit test, which prevents us from knowing if a
type fruit or veggie doesn't have a set seed in the tests. The only path
that needs to be blacklisted is the common `/obj/item/food/grown` path
itself, since its seed variable needs to remain null so that we can be
warned about any subtype that hasn't overriden that value.
This PR also removes the `/obj/item/food/grown/shell` path which serves
no purpose anymore.
## Why It's Good For The Game
Backend improvements. Atomizing changes from my refactor.
## Changelog
N/A
9154e28668